This post follows on from my previous post about sensors and was inspired by one of the questions asked following that post.
While sensor size does have some effect on low light performance, the biggest single factor is really the lens. It isn’t really bigger sensor that has revolutionised low light performance. It’s actually the lenses that we can use that has chnge our ability to shoot in low light. When we used to use 1/2″ or 2/3″ 3 chip cameras for most high end video production the most common lenses were the wide range zoom lenses. These were typically f1.8 lenses, reasonably fast lenses.
But the sensors were really small, so the pixels on those sensors were also relatively small, so having a fast lens was important.
Now we have larger sensors, super 35mm sensors are now common place. These larger sensors often have larger pixels than the old 1/2″ or 2/3″ sensors, even though we are now cramming more pixels onto the sensors. Bigger pixels do help increase sensitivity, but really the biggest change has been the types of lenses we use.
Let me explain:
The laws of physics play a large part in all of this.
We start off with the light in our scene which passes through a lens.
If we take a zoom lens of a certain physical size, with a fixed size front element and as a result fixed light gathering ability, for example a typical 2/3″ ENG zoom. You have a certain amount of light coming in to the lens.
When the size of the image projected by the rear of the lens is small it will be relatively bright and as a result you get an effective large aperture.
Increase the size of the sensor and you have to increase the size of the projected image. So if we were to modify the rear elements of this same lens to create a larger projected image (increase the image circle) so that it covers a super 35mm sensor what light we have. is spread out “thinner” and as a result the projected image is dimmer. So the effective aperture of the same lens becomes smaller and because the image is larger the focus more critical and as a result the DoF narrower.
But if we keep the sensor resolution the same, a bigger sensor will have bigger pixels that can capture more light and this makes up for dimmer image coming from the lens.
So where a small sensor camera (1/2″, 2/3″) will typically have a f1.8 zoom lens when you scale up to a s35mm sensor by altering the projected image from the lens, the same lens becomes the equivalent of around f5.6. But because for like for like resolution the pixels size is much bigger, the large sensor will be 2 to 3 stops more sensitive, so the low light performance is almost exactly the same, the DoF remains the same and the field of view remains the same (the sensor is larger, so DoF decreases, but the aperture becomes smaller so DoF increases again back to where we started). Basically it’s all governed by how much light the lens can capture and pass through to the sensor.
It’s actually the use of prime lenses that are much more efficient at capturing light has revolutionised low light shooting as the simplicity of a prime compared to a zoom makes fast lenses for large sensors affordable. When we moved to sensors that are much closer to the size of sensors used on stills cameras the range and choice of affordable lenses we could use increased dramatically. We were no longer restricted to expensive zooms designed specifically for video cameras.
Going the other way. If you were to take one of todays fast primes like a common and normally quite affordable 50mm f1.4 and build an optical adapter of the “speedbooster” type so you could use it on a 2/3″ sensor you would end up with a lens the equivalent of a f0.5 10mm lens that would turn that 2/3″ camera into a great low light system with performance similar to that of a s35mm camera with a 50mm f1.4.
I’ve been shooting with the Fujinon MK18-55mm lens on my PXW-FS7 and PXW-FS5 since the lens was launched. I absolutely love this lens, but one thing has frustrated me: I really wanted to be able to use it on my PMW-F5 to take advantage of the 16 bit raw. Finally my dreams have come true as both Duclos and MTF have started making alternate rear mounts for both the MK18-55mm and the MK50-135mm.
So, when Fujinon contacted me and asked if I would be interested in shooting a short film with these lenses on my F5 I jumped at the chance. The only catch was that this was just over a week ago and the video was wanted for IBC which means it needed to be ready yesterday. And of course it goes without saying that it has to look good – no pressure then!
First challenge – come up with something to shoot. Something that would show off the key features of these beautiful lenses – image quality, weight, macro etc. I toyed with hiring a model and travelling to the Irish or Welsh coast and filming along the cliffs and mountains. But it’s the summer holidays so there was a risk of not being able to get an isolated location all to ourselves, plus you never know what the weather is going to do. In addition there was no story, no beginning, middle or end and I really wanted to tell some kind of story rather than just a montage of pretty pictures.
So my next thought was to shoot an artist creating something. I spent a weekend googling various types of artistry until I settled on a blacksmith. The video was going to be shown in both SDR and HDR and fire always looks good in HDR. So after dozens of emails and telephone calls I found an amazing looking metalwork gallery and blacksmith that was willing for a reasonable fee to have me and another cameraman take over their workshop for a day (BIG thank you to Adam and Lucy at Fire and Iron check out their amazing works of art).
Normally I’d carry out a recce of a location before a shoot to take photos and figure out what kind of lights I would need as well as any other specialist or unusual equipment. But this time there simply wasn’t time. We would be shooting the same week and it was already a very busy week for me.
The next step before any shoot for me is some degree of planning. I like to have a concept for the video, at the very least some outline of the shots I need to tell the story, perhaps not a full storyboard, but at least some kind of structure. Once you have figured out the shots that you want to get you can then start to think about what kind of equipment you need to get those shots. In this case, as we would be shooting static works of art I felt that having ways to move the camera would really enhance the video. I have a small Jib as well as some track and a basic dolly that is substantial enough to take the weight of a fully configured PMW-F5 so these would be used for the shoot (I’m also now looking for a slider suitable for the F5/F55 that won’t break the bank, so let me know if you have any recommendations).
So the first items on my kit list after the camera and lenses (the lenses were fitted with Duclos FZ rear mounts) was the jib and dolly. To achieve a nice shallow depth of field I planned to shoot as close to the lenses largest aperture of T2.9 as possible. This presents 2 challenges. The F5’s internal ND filters go in 3 stop steps – that’s a big step and I don’t want to end up at T5.6 when really I want T2.9, so 1 stop and 2 stop ND filters and my gucchi wood finished Vocas matte box would be needed (the wood look does nothing to help the image quality, but it looks cool). Oh for the FS7 II’s variable ND filter in my F5!
The second problem of shooting everything at T2.9 with a super 35mm sensor is that focus would be critical and I was planning on swinging the camera on a jib. So I splashed out on a new remote follow focus from PDMovie as they are currently on offer in the UK. This is something I’ve been meaning to get for a while. As well as the remote follow focus I added my Alphatron ProPull follow focus to the kit list. The Fujinon MK lenses have integrated 0.8 pitch gears so using a follow focus is easy. I now wish that I had actually purchased the more expensive PDMovie follow focus kit that has 2 motors as this would allow me to electronically zoom the lens as well as focus it. Oh well, another thing to add to my wish list for the future.
One other nice feature of the Fujinon MK’s is that because they are parfocal you can zoom in to focus and then zoom out for the wider shot and be 100% sure that there is no focus shift and that the image will be tack sharp. Something you can’t do with DSLR lenses.
Lighting: This was a daylight shoot. Now I have to say that I am still a big fan of old school tungsten lighting. You don’t get any odd color casts, it gives great skin tones, it’s cheap and the variety and types of lamp available is vast. But as we all know it needs a lot of power and gets hot. Plus if you want to mix tungsten with daylight you have to use correction gels which makes the lights even less efficient. So for this shoot I packed my Light and Motion Stella lamps.
The Stellas are daylight balanced LED lamps with nice wide 120 degree beams. You can then use various modifiers to change this. I find the 25 degree fresnel and the Stella 5000 a particularly useful combination. This is the equivalent to a 650W tungsten lamp but without the heat. The fresnel lens really helps when lighting via a diffuser or bounce as it controls the spill levels making it easier to control the overall contrast in the shot. The Stella lights have built in batteries or can be run from the mains. They are also waterproof, so even if it rained I would be able to have lights outside the workshop shining in through the windows if needed.
I always carry a number of pop-up diffusers and reflectors of various sizes along with stands and arms specifically designed to hold them. These are cheap but incredibly useful. I find I end up using at least one of these on almost every shoot that I do. As well as a couple of black flags I also carry black drapes to place on the floor or hang from stands to reduce reflections and in effect absorb unwanted light.
To check my images on set I use an Atomos Shogun Flame. Rather than mounting it on the camera, for this shoot I decided to pack an extra heavy duty lighting stand to support the Shogun. This would allow my assistant to use the flame to check focus while I was swinging the jib. The HDR screen on the Shogun allows me to see a close approximation of how my footage will look after grading. It also has peaking and a zoom function to help with focussing which was going to be essential when the camera was up high on the jib and being focussed remotely. I also included a TV-Logic LUM171G which is a 17″ grading quality monitor with 4K inputs. The larger screen is useful for focus and it’s colour accuracy helpful for checking exposure etc.
For audio I packed my trusty UWP-D wireless mic kit and a pair of headphones. I also had a shotgun mic and XLR cable to record some atmos.
As well as all the larger items of kit there’s also all the small bits and bobs that help a shoot go smoothly. A couple of rolls of gaffer tape, crocodile clips, sharpies, spare batteries, extension cables etc. One thing I’ve found very useful is an equipment cart. I have a modiffied rock-n-roller cart with carpet covered shelves. Not only does this help move all the kit around but it also acts as a desk on location. This is really handy when swapping lenses or prepping the camera. It can save quite a bit of time when you have a mobile work area and somewhere you can put lenses and other frequently used bits of kit.
The day before the shoot I set everything up and tested everything. I checked the backfocus adjustment of the lenses. Checked the camera was working as expected and that I had the LUT’s I wanted loaded into both the camera and the Gratical viewfinder. With the camera on the jib I made sure I had the right weights and that everything was smooth. I also checked that my light meter was still calibrated against the camera and that the lens apertures matched what I was expecting (which they did perfectly). Color temperature and colorimetry was checked on the TVLogic monitor.
It’s worth periodically checking these things as there would be nothing worse than rocking up for the shoot only to find the camera wasn’t performing as expected. If you rent a cinema camera package from a major rental house it would be normal to set the camera up on a test bench to check it over before taking it away. But it’s easy to get lazy if it’s your own kit and just assume it’s all OK. A full test like this before an important shoot is well worth doing and it gives you a chance to set everything up exactly as it will be on the shoot saving time and stress at the beginning of the shoot day.
On the morning of the shoot I loaded up the car. I drive a people carrier (minivan to my friends in the USA). Once you start including things like a jib, track and dolly, equipment cart, 6x tungsten lights, 4 x LED lights, plus camera, tripods (including a very heavy duty one for the jib) the car soon fills up. A conventional saloon would not be big enough! One word of caution. I was involved in a car crash many years ago when the car rolled over. I had camera kit in the back of the car and the heavy flight cases did a lot of damage crashing around inside the car. If you do carry heavy kit in the car make sure it’s loaded low down below the tops of the seats. You don’t want everything flying forwards and hitting you on the back of your head in a crash. Perhaps consider a robust steel grill to put between the cargo compartment and the passenger compartment.
On arrival at the location, while it’s very tempting to immediately start unloading and setting up, I like to take a bit of a break and have a tea or coffee first. I use this time to chat with the client or the rest of the crew to make sure everyone knows what’s planned for the day. Taking a few minutes to do this can save a lot of time later and it helps everyone to relax a little before what could be a busy and stressful day.
Now it’s time to unpack and setup. I find it’s better to unpack all the gear at this time rather than stopping and starting throughout the day to unpack new bits of kit. Going to the car, unlocking, unpacking, locking, back to the set etc wastes time. This is where the equipment cart can be a big help as you can load up the cart with all those bits and pieces you “might” need… and inevitably do need.
The blacksmiths workshop was a dark space about 6m x 5m with black walls, open on one side to the outside world. Blacksmiths forges (so I learnt) are dark so that the blacksmith can see the glow of the metal as it heats up to gauge it’s temperature. On the one hand this was great – huge amounts of relatively soft light coming from one direction. On the other hand the dark side was very dark which would really push the camera and lenses due to the extreme contrast this would create.
We set the jib up inside the workshop to shoot the various processes used by a blacksmith when working with iron and steel. Apparently there are only 7 different processes and anything a blacksmith does will use just these 7 processes or variations of them.
Most of the shots done on the jib would be shot using the Fujinon MK18-55mm, so that’s the lens we started with. For protection from flying sparks a clear glass filter was fitted to the lens. While the finished film would be a 24p film, most of the filming was 4K DCI at 60fps recording to 16 bit raw. This would give me the option to slow down footage to 24p in post if I wanted a bit of slow motion.
When we did need to do a lens swap it was really easy. The Vocas matte box I have is a swing-away matte box. So by releasing a lever on the bottom of the matte box it swings out of the way of the lens without having to remove it from the rods. Then I can remove the lens and swap it to the other lens. The MK50-135mm is the same size as the MK18-55mm. The pitch gears are also in the same place. So swapping lenses is super fast as the follow focus or any focus motors don’t need to be re-positioned and the matte box just swings back to exactly the same position on the lens. It’s things like this that really separate pro cinema lenses from DSLR and photography lenses.
For exposure I used the cameras built in LUT’s and the 709(800) LUT. I set the camera to 800EI. I used a grey card to establish a base exposure, exposing the grey card at 43% (measuring the 709 level). I used a Zacuto Gratical viewfinder which has a great built in waveform display, much better than the one in the camera. I also double checked my light levels with a light meter. I don’t feel that it’s essential to use a light meter but it’s a useful safety net. The light meter is also handy for measuring contrast ratios across faces etc but again if you have a decent waveform display you don’t have to have a light meter.
For the next 3 hours we shot the various processes seen in the video. Trying to get a variety of different shot. But when each process is quite similar, usually involving the anvil and a large hammer it was difficult to come up with shots that looked different.
In the afternoon we set up to shoot the interview sequence. The reason for doing this was to not only provide the narrative for the film but also to help show how the lenses reproduce skin tones. The Fujinon MK series lenses are what I would describe as “well rounded”. That is, not too sharp but not soft either. They produce beautifully crisp pictures without the pictures looking artificially sharp and this really helps when shooting people and faces. They just look really nice.
For the interview shot I used one of the Stella 5000 lights with the 25 degree fresnel lens aimed through a 1m wide diffuser to add a little extra light to supplement the daylight. This allowed me to get some nice contrast across the blacksmiths face and nice “catch light” highlights in his eyes. In addition the little bit of extra light on his face meant that the back wall of the forge would appear just that bit darker due to the increased contrast between his face and the back wall. This is why we light…. not just to ensure enough light to shoot with, I had plenty of light, if I remember right I had a 1 stop ND in the matte box. But to create contrast, it’s the contrast that gives the image depth, it’s contrast that makes an image look interesting.
The final stage was to shoot the treasure chest and ornate jars that would show off the the lenses macro and close up performance. The treasure chest is a truly amazing thing. It weighs around 80kg. The locking mechanism is quite fascinating and I still struggle to believe that it was all hand made. The small metal jars are made out of folded and welded steel. It’s the folds in the metal that create the patterns that you see.
Once again we used the jib to add motion to the shots. I also used the macro function of both the MK18-55mm and MK50-135mm lenses. This function allows you to get within inches of the object that you are shooting. It’s a great feature to have and it really adds to the versatility of these lenses.
We wrapped at 7pm. Time to pack away the kit. It’s really important not to rush at this stage. Like everyone else I want to get home as quick as I can. But it’s important to pack your kit carefully and properly. There is nothing more annoying than when you start prepping for the next shoot finding that something has been broken or is missing because you rushed to pack up at the end of the previous shoot. Once you have packed everything away don’t forget to do that last walk through all the locations you’ve shot in to make sure you haven’t forgotten something.
I shot a little over hour of material. As it was mostly 60p 4K raw that came to about 1.5TB This was backed up on site using a Nexto-DI NSB25 which is a stand alone device that makes 2 verified copies of everything on 2 different hard drives. The film was edited using Adobe Premiere CC which handles Sony’s raw very easily. Grading was completed using DaVinci Resolve. I spent 2 days editing and a day grading the first version of the film. Then I spent another day re-grading it for HDR and producing the different versions that would be needed. All in, including coming up with the concept, finding the location, prepping, shooting and post took it took about 7 to 8 full work days to put this simple 4 minute film together.
Prepping my camera today for a shoot tomorrow. I’ll be shooting with the Fujinon MK18-55mm and MK50-135mm lenses fitted with Duclos FZ mount adapters. I’ve been using the MK18-55mm on my FS7 and FS5 for some time and I have to say I really love this lens. It produces beautiful images with silky smooth bokeh, it’s parfocal and it covers a very hand range of focal lengths. I’ve been wanting to use this lens on my F5 for some time and now at last I can. These lenses work great on the F5 and F55. They are very light compared to most PL lenses and this really helps with the cameras balance, especially if shooting handheld. They are also very cost effective.
The light lens weight means I need less weight on my jib than I would have with most similar PL zoom lenses. Also being nice and fast at T2.9 I know I can get great shallow DoF. Tomorrow I’m going to be shooting 2 amazing artists that create incredibly detailed things out of large lumps of iron and steel. I’ll be shooting examples of some of the finest works of metallic art along with all the key parts of the process of creating them. There will be beauty, iron, steel, heat, flames and sparks. I’ll try to post pictures from the shoot over the weekend and once the video is done it will be online for all to enjoy.
Having done a fair bit of shooting with the new and very nice Fujinon MK 18-55mm E-Mount lens I decided to take a much closer look at the Fujinon Cabrio XK6x20 20 to 120mm T3.5 lens with the servo hand grip.
The price of this lens is very competitive and it can now be found as low as £11K/$16K. Lets not try to pretend that good quality PL mount zooms are cheap, but this is a great price for what is very high quality glass. The 20 to 120mm zoom range is nice and of course it’s truly parfocal there is a back focus adjuster along with macro function.
Like the other similar ENG style PL zooms this lens is quite heavy. The front element of the lens is huge and I’m sure a lot of the weight comes from this big lump of glass. One of the nice things about this lenses baby brother the MK 18-55, is that the 18-55 is really very light, which is great on the smaller cameras like the FS5 or FS7.
The 20-120mm Cabrio exudes quality. The build quality of the lens is wonderful, the witness marks are crisp and well engraved, the servo zoom is silky smooth. The large servo module acts as a handgrip just like traditional ENG lenses and it really comfortable to hold and use this way. But if you don’t need it it can be easily removed leaving the bare bones lens body and saving a little bit of weight. There are the usual 0.8 mod pitch gears on each of the focus zoom and iris rings. Focus ring travel is huge at about 200 degrees and due to the physical size of the lens this is as much as I’d ever want. Even towards infinity there is still a nice range of travel so focussing accurately on distant objects is easy.
But what about the image quality, how does the lens perform in real world situations?
To find out I used it for a shoot in Norway. The shoot was for TV manufacturer Philips. We wanted to obtain some high quality 4K HDR footage to show off the capabilities of a new 4K OLED Ambilight TV. Unfortunately the weather conditions on the shoot were pretty grim most of the time and this made it all the more challenging. But I’m pleased to say that both lenses performed very well despite snow, ice and cold.
One of the great things about having both the high end Cabrio 20-120mm and the budget friendly 18-55mm for the shoot was that the overall look of the images from the FS5 and F5 was the same. Often mixing lenses from different manufacturers results in different looking images giving the colourist more work to do in post. Fujinon now have a range of lenses to suit most budgets from the high end Cabrio 19-90mm T2.9 down through the Cabrio 20-120 T3.5 to the MK 18-55 T2.9.
So what do the images from these lenses look like? I’m afraid I can’t show any of the footage from the Philips shoot yet, I should be able to show it later in the year. Below are a couple of frame grabs to give you an idea of the kind of images you can get. We didn’t shoot the same shots with the F5/XK6x20 and FS5/MK18-55 at the same time, I was the only cinematographer. So I don’t have a side by side comparison from the shoot, but the different scenes shot with each lens/camera combo match really well.
TESTING BOTH LENSES:
In order to better directly compare the two lenses I shot some test shots. The XK6x20 on my F5 and the MK18-55 on my FS7. Both cameras were set to the same settings and hypergamma 3 with the cinema matrix used. The images you will see below have not been touched, this is how they looked straight from the camera. If you click on the picture you should get a link to the full frame 4K image, but do remember this are Jpegs.
I tried to get the same shots with both combinations but you will see some small variations. I apologise for that. To give as fair a comparison as possible I did most of the shots at 20mm and 55mm, but then in addition shot at 18mm on the MK18-55 and 120mm on the XK6X20 so you can see the additional range each lens offers.
First test was of a neighbours Cherry tree in blossom.
The next test was a simple setup shot of a couple of beer bottles on a table with strong sunlight from above and behind to create deep contrast. I wanted to see if either lens showed signs of loosing shadow detail due to the very large, very bright table top introducing flare into the shadows.
My conclusion with the above shots is that there is remarkably little difference between these two lenses. Both perform extremely well. I think the XK6X20 might be marginally sharper at the wide end than the 18-55mm, either that or the slightly better viewfinder of the F5 is allowing me to focus more precisely. In addition I think the bokeh of the more expensive Cabrio is marginally smoother than the 18-55, but again it’s a tiny difference (not as big as the difference in white balance of the two cameras).
Finally a shot of my ugly mug just so you can take a look at some skin tones.
Again very little difference between these lenses which is a good thing. Both perform very well, both produce pleasing images. Sure the XK6X20 20-120mm is more than twice the price of the MK18-55 but then it does offer twice the zoom range and it’s very hard to make fast parfocal lenses with big zoom ranges for large sensors. There will be a companion MK50-135mm lens coming later in the year, so with both the MK lenses you will be able to get the full range of the XK6X20 and a bit more, provided you don’t mind swapping lenses. It’s a tough choice if you have an E-mount Sony camera, which to get? For E-Mount I think the pair of MK lenses will be the way to go. If you have a PL mount camera the XK6X20 has to be a very serious contender. It’s a great all-round cinema zoom lens and a realistic price. Whichever way you do go you won’t be disappointed, these are proper cinema lenses.
I have just return from one of the most challenging shoots I have been involved in. The shoot took place over 5 days in and around Tromso in Norway. The aim was to gather footage to show off the capabilities of a new type of 4K TV from Phillips.
We shot the Northern Lights, we shot dog sledding , snow mobiles, shots of the city and sailing on the fjords. Each part of the shoot had many challenges and a lot of the shoot took place at night and at night the crew slept in cabins, tents and on the yachts. Shooting from the ice and snow covered deck of a yacht in temperatures well below zero is not something I enjoyed. And to top it all off the weather was pretty grim fro most of the shoot. Heavy snow showers, freezing temperatures and towards the end strong winds.
Because image quality is paramount for this project I choses to use the best lenses I could, but at the same time space and time constraints dictated that zoom lenses would be desirable. We were shooting 16 bit raw as well as XAVC class 480 on my PMW-F5 and some pick-up shots in UHD XAVC-L on a PXW-FS5. For the PMW-F5 the primary lens was the Fujinon Cabrio XK6x20, 20-120mm PL zoom and to ensure we had similar looking images from the FS5 I used the new Fujinon XF 18-55mm. I have to say that I’m quite in love with both of these lenses.
The Cabrio 20-120 is a beautiful lens and it’s really nice to have a servo zoom that is truly parfocal. The 20-120 produces really nice images even in the most challenging of conditions and at T3.5 it’s reasonably fast throughout the entire zoom range. This was the lens that I used for the majority of the shoot, in particular for the many night scenes we shot. The E-Mount 18-55 on the FS5 produces images that matched really well with the bigger lens and camera. This is a combination I would love to use on more shoots where the budget will allow.
One particular scene that we had to shoot was particularly challenging. It was a set up shot of a night time arrival of a couple of snowmobiles at a Sami camp site. The Sami people are the indigenous people of Northern Norway and they have a particular style of tent know as a Laavu which is similar to a teepee or wigwam. The idea behind the shot was to have the snow scooters arriving with headlights blazing and for the drivers to then enter the tent lit only by the light of a campfire inside the tent. At the time of the shoot it was snowing heavily and was totally dark. Turn off the lights of the snowmobiles and you could not see a thing.
While modern cameras like the F5 are very sensitive, the light of a campfire inside a tent will not adequately light a scene like this on it’s own. I didn’t want a totally dark background, so I decided that I would subtly light the trees of the forest that we were in to add some drama and give some depth to the background and a sense of being in a forest.
As we were travelling continuously on this shoot there was no space for a large or complex lighting kit and the remote location meant we needed battery powered lights. In addition I knew before we left that there was a chance of bad weather so I needed lights that would work whatever mother nature decided to throw at us.
I decided to take a set of 3 Light & Motion Stella battery powered LED lights. It’s just as well I had the Stella lamps as on top of all the other difficulties of the shoot the weather decided it was not going to play ball. We had to shoot the scene (and much of the shoot) in the middle of a snow storm. Fortunately the Stella lights are completely waterproof, so I didn’t need to worry about rain or snow protection. Just set them up turn them on and use the built in dimmer to set the light output.
To light the scene I set up a Stella Pro 5000 in the woods behind the Sami tent, aimed through the trees and pointed directly towards the camera. I chose to backlight the trees to provide a sense of there being trees rather than lighting them. I felt this would look less lit than throwing a ton of light into the forest from the front and I’m pleased with the result.
The Stella Pro 5000 is very bright for a compact battery operated light, it’s 5000 lumen 120 degree output that is pretty close to what you would get from a 200W HMI, it’s very bright. It has a very high CRI and gives out great quality daylight balanced light. It was positioned so that the light itself was behind the tent on a small bank, about 20m back in the woods. You couldn’t see it in the shot, but the light coming through the trees created shafts of light in the snow and the trees appeared as silhouettes. It added depth and interest to what would have otherwise been a near totally black background.
Then to provide a small amount of light so that we could see the riders of the snow scooters as they walked to the tent I used a Stella 2000. I didn’t really want the light from this lamp to be too obvious as this would really make the scene look “lit”. I didn’t need the full 2000 lumen output so I used the built in dimmer to reduce the output to around 70%.
The third light was a small Stella 1000 and this was placed inside the tent with a scrunched up orange gel. The Stella 1000 would typically be used as a camera top light, but it’s full dimmable and produces a very high light quality, making it suitable for many applications. The creases and folds in the orange gel helped break up the light a little creating a less lit look sympathetic to the fire inside the tent.
It allowed me to increase the illumination in the tent, adding to the light from the fire without it being obvious that the tent interior was lit. For some of the shots I had an assistant sit in the tent, out of shot and slowly move the gel in front of the light to add a little movement to the light to mimic the firelight even better.
At the moment I can’t show you the footage. That will have to wait until after the launch of the TV. But I’m really pleased with the way this scene came out. It’s challenging trying to shoot in the dark, in a blizzard, in temperatures well below freezing. Every aspect of getting this scene was hard. Opening a flight case to get out some kit meant getting snow on everything inside it. Just positioning the light up the woods was tough, the snow was up above my knees as I waded through it. Operating the camera is so much harder when it has a rain cover on it. The viewfinder was constantly misting up as snow fell on it non stop. Seeing the witness marks on the lens is difficult (although thankfully the marks on the Fujinon 20-120 are huge and easy to see).
But sometimes it’s challenges like these that make the job interesting. I know I was cursing and swearing at times trying to make these shots work, but seeing the scene come to life in the grade is all the more rewarding.
I’ll be writing more about the Fujinon 20-120 very soon, so why not subscribe to my blog using the subscribe bottom on the left.
At long last Samyang have filled the gap in their vDSLR lens line up! It was crazy not to have a 50mm lens. Finally they are launching a 50mm T1.5 lens with pitch gears etc. This lens will be available next month (September) so not too long to wait. It’s full frame so should work great with the A7s as well as all your Super35 and APS-C cameras.
Hop over to the Samyang web site for sample images and further information. I have one on pre-order as as soon as I can I will check it out.
Blue and purple fringes around edges in photos and videos are nothing new. Its a problem we have always had. telescopes and binoculars can also suffer. It’s normally called chromatic aberration or CA. When we were all shooting in standard definition it wasn’t something that created too many issues, but with HD cameras and 4K cameras it’s a much bigger issue because as you increase the resolution of the system (camera + lens) generally speaking, CA becomes much worse.
As light passes through a glass lens the different wavelengths that result in the different colours we see are diffracted and bet by different amounts. So the point behind the lens where the light comes into sharp focus will be different for red light to blue light.
The larger the pixels on your sensor the less of an issue this will be. Lets say for example that on an SD sensor with big pixels, when the blue light is brought to best focus the red light is out of focus by 1/2 a pixel width. All you will see is the very slightest red tint to edges as a small bit of out of focus red spills on to the adjacent pixel. Now consider what happens if you increase the resolution of the sensor. If you go from SD to HD the pixels need to made much smaller to fit them all on to the same size sensor. HD pixels are around half the size of SD pixels (for the same size sensor). So now that out of focus red light that was only half the width of an SD pixel will completely fill the adjacent pixels so the CA becomes more noticeable.
In addition as you increase the resolution of the lens you need to make the focus of the light “tighter” and less blurred to increase the lenses resolving power. This has the effect of making the difference between the focus points of the red and blue light more distinct, there is less blurring of each colour, so less bleed of one colour into the other and as a result more CA as the focus point for each wavelength becomes more distinct. When each focus point is more distinct the difference between the in focus and out of focus light becomes more obvious, so the colour fringing becomes more obvious.
This is why SD lenses very often show less CA than HD lenses, a softer more blurry SD lens will have less distinct CA. Lens manufacturers will use exotic types of glass to try to combat CA. Some types of glass have a negative index so blue may focus closer than red and then other types of glass may have a positive index so red may focus closer than blue. By mixing positive and negative glass elements within the lens you can cancel out some of the colour shift. But this is very difficult to get right across all focal lengths in zoom lenses so some CA almost always remains. The exotic glass used in some of the lens elements can be incredibly expensive to produce and is one of the reasons why good lenses don’t come cheap.
Rather than trying to eliminate every last bit of CA optically the other approach is to electronically reduce the CA by either shifting the R G B channels in the camera electronically or reducing the saturation around high contrast edges. This is what ALAC or CAC does. It’s easier to get a better result from these systems when the lens is precisely matched to the camera and I think this is why the CA correction on the Sony kit lenses tends to be more effective than that of the 3rd party lenses.
Sony recently released firmware updates for the PMW200 and PMW300 cameras that improves the performance of the electronic CA reduction of these cameras when using the supplied kit lenses.
Some people are struggling with lens options for the Sony half inch interchangeable lens cameras. Many try to use 2/3″ lenses via the ACM-21 with disappointing results. Lenses are designed to meet certain criterion. The lenses for the PMW-EX3 and PMW-320 actually perform very well, yet these are inexpensive lenses, so why when you use a much more expensive 2/3″ ENG zoom lens can the results be disappointing?
There is a very big difference between the way most typical ENG lens focus and the way an EX1/3, PMW-320 or PMW-200 lens focusses. An ENG lens will be a Par Focal lens, a lens that maintains constant focus throughout the zoom range. This is incredibly difficult to design especially with large zoom ranges and is one of the reasons ENG zooms are normally expensive pieces of glass.
The lenses used on the EX1/EX3, PMW-320 are not Par Focal, this makes them much cheaper, the focus shifts and changes as you zoom….. But clever electronics inside the camera and lens compensates for this by adjusting the lenses focus as you zoom so that in practice the lens appears to stay in perfect focus. An electronically compensated lens like this is lower cost to produce than a sophisticated typical ENG type zoom and makes the lens compact and lightweight as well as much cheaper.
Another factor is that as you increase the resolution of a lens, trying to bring everything in to focus on an ever smaller point, you run in to more and more problems with chromatic aberrations. Different wavelengths (and thus colours) of light get bent by different amounts when they pass through a glass lens. As you make the focussed light for one single colour smaller and sharper, the other colours of the spectrum become more dispersed. As a result, generally a softer lens, for example an SD lens (lower MTF) will exhibit fewer colour aberrations than a sharper HD lens. To compensate for these aberrations lens manufactures use very exotic types of glass with different refraction indexes to try to cancel out or at least minimise CA (chromatic aberration), but this glass is extremely expensive. The higher the resolution of the lens, the more expensive the glass gets.
With a camera like the EX1/EX3, PMW-320, PMW-200 when you know the exact characteristics of the lens (as they all use essentially the same lens) instead of employing exotic glass, you can program the camera to electronically remove or reduce the appearance of the CA and this happens inside the EX1/EX3, 320 and PMW-200 etc.
Next you must take in to account pixel size. In simple terms to work with the resolution of the cameras sensor, the lens has to be able to focus a point of light small enough to hit only one pixel. A typical 2/3″ HD camera has much bigger pixels that the pixels on the 1/2″ sensor of the PMW-320. As a result a lens that is only just able to achieve HD resolution on a 2/3″ camera, will not achieve HD resolution on the PMW-320 with it’s smaller pixels, it’s simply not designed to work with such small pixels. This means that you really need an HD lens designed for the 1/2″ sensor size and the corresponding pixel size.
These factors combined mean that the standard kit lens on the EX3, PMW-320 etc appears to perform very well and it takes a much more expensive, designed for 1/2″ lens to even match this apparent performance in most cases. Perhaps the new 16x lens coming for the PMW-300 will be available to purchase on it’s own. This would offer EX3 and PMW-320 owners the option of a high performing lens with a greater zoom range, probably for less than a similar performance conventional lens.
This came up as a question in response to the post about my prototype lens adapter. The adapter is based around an electronic Canon EF mount and the question was, what do I think about DSLR zooms?
There is a lot of variation between lenses when it comes to sharpness, contrast and distortions. A zoom will always be a compromise compared to a prime lens. DSLR lenses are designed to work with 24MP sensors. A 4K camera only has around 9MP, so your working well within the design limits of the lens even at 4K. While a dedicated PL mount zoom like an Angenieux Optimo will most likely out perform a similar DSLR zoom. The difference at like for like apertures will not be huge when using smaller zoom ratios (say 4x). But 10x and 14x zooms make more compromises in image quality, perhaps a bit of corner softness or more CA and these imperfections will be better or worse at different focal lengths and apertures. At the end of the day zooms are compromises but for many shoots it may simply be that it is only by accepting some small compromises that you will get the shots you want. Take my storm chasing shoots. I could use primes and get better image quality, but when you only have 90 seconds to get a shot there simply isn’t time to swap lenses, so if you end up with a wide on the camera when a long lens is what is really needed, your just not going to get the shot. Using a zoom means I will get the shot. It might not be the very best quality possible but it will look good. It is going to be better than I could get with an HD camera and a very slightly compromised shot is better than no shot at all.
If the budget would allow I would have a couple of cameras with different prime lenses ready to go. Or I would use a big, heavy and expensive PL zoom and have an assistant or team tasked solely with getting the tripod set up and ready asap. But my budget isn’t that big. I could spend weeks out storm chasing before I get a decent shot, so anything I can do to minimise costs is important.
It’s all about checks and balances. It is a compromise, but a necessary one. It’s not a huge compromise as I suspect the end viewer is not going to look at the shot and say “why is that so soft” unless they have a side by side, like for like shot to compare. DSLR zooms are not that bad! So yes, using a DSLR zoom is not going to deliver quality to match that of a similar dedicated PL zoom in most cases, but the difference is likely to be so small that the end viewer will never notice and thats a compromise I’m prepared to accept in order to get a portable camera that shoots 4K with a 14x zoom lens.
What about DSLR primes and why have I chosen the Canon Mount?
This is where the image performance gap gets even narrower. A high quality DSLR prime can perform just as well as many much more expensive PL mount lenses. The difference here is more about the usability of the lens. Some DSLR lenses can be tiny and this makes them fiddly to use. They are all All sorts of sizes, so swapping lenses may mean swapping Matte boxes or follow focus positions etc. Talking of focus, very often the focus travel on a DSLR lens is very, very short so focussing is fiddly. If the lens has an aperture ring it will probably have click stops making smooth aperture changes mid shot difficult. My prime lenses are de-clicked or never had clicks in the first place (like the Samyang Cine Primes). It’s not so much the issue of requiring a finer step than the one stop click, but more the ability to pull aperture during the shot. It’s not something I need to do often, but if I suddenly find I need to do it, I want a smooth aperture change. That being said, one of the issues with using Canon EF lenses with their electronic iris is that they operate in 1/8th stop steps and this is visible in any footage. Ultimately I am still committed to using the Canon mount lenses simply because there are so many to choose from and they focus in the right direction unlike Nikon lenses which focus back to front. For primes I’m using the excellent and fully manual Samyang T1.5 Cine Primes. I really like these lenses and they produce beautiful images at a fraction of the price of a PL mount lens. My zoom selection is a bit of a mish-mash. One thing about having a Canon mount on the camera is that I can still use Nikon lenses if I fit the lens with a low cost Nikon to Canon adapter ring. If you do this you can only use lenses with an actual iris ring, so generally these are slightly older lenses, but for example I have a nice Sigma 24-70mm f2.8 with a manual iris ring (and it focusses the RIGHT way, like most Sigmas but unlike most Nikon mount lenses). In addition I have a 70-300mm f4 Nikon mount Sigma as well as an Old Tokina 28-70mm f2.6 (lovely lens, a little soft but very nice warm colour). One thing I have found is that most of the Nikon to Canon adapter rings are little bit on the thin side. This prevents any zooms from being Parfocal as it puts the back focus out. Most of the adpaters are made in two parts and it’s quite easy to take the front and back parts apart and add shims made out of of thin plastic sheet or even card between the two halves to correct the back focus distance.
So there you have it. Overall DSLR lenses are not a huge compromise. Of course I would love to own a flight case full of good quality PL mount, 4K ready, glass. Perhaps one day I will, but it’s a serious investment. Currently I use DSLR lenses for my own projects and then hire in better glass where the budget will allow. For any commercials or features this normally means renting in a set of Ultra Primes or similar. I am keeping a close eye on the developments from Zunow. I like their 16-28mm f2.8 and the prototype PL primes I saw at NAB look very good. I also like the look of the Zeiss 15.5 to 45 light weight zoom. Then of course there is the excellent Fujinon 19-90mm Cabrio servo zoom, but these are all big bucks. Hopefully I’ll get some nice big projects to work on this year that will allow me to invest in some top end lenses.
Just a quick note on a rather obscure subject. I do a lot of 3D work. Buying pairs of PL mount lenses for my F3’s is beyond my budget right now, so I hire in lenses when I need them. However for my own projects I use DSLR lenses, mainly Nikkors and Tokina’s. One thing that i have discovered is that many of the older manual Nikkors have a tendency to shift the image left and right when you focus. This then miss-aligns the rig. The more modern internal focussing lenses are much, much better in this respect with little or no shift at all. The only problem with the more modern IF lenses is that they often don’t have iris rings (so iris is adjusted with a MTF adapter) and the focus control often has a slipping clutch making repeatable focussing a little harder. So neither is perfect. For 3D applications I think the more modern IF lenses are preferable.
Camera setup, reviews, tutorials and information for pro camcorder users from Alister Chapman.