Category Archives: lenses

A Review of the Tokina Vista Prime Lenses

I was recently given the opportunity shoot some test footage with a Sony Venice II.  A camera like Venice needs good glass, so I put out some feelers to see what lenses I could get for the shoot. I was offered the use of a set of the Tokina Vista primes, lenses I have been wanting to try for some time, so this was the perfect opportunity to try these interesting lenses on Sony’s newest cinema camera.

DSC_0298-600x450 A Review of the Tokina Vista Prime Lenses
Shooting at Tower Bridge London with the Tokina Vista 135mm and Venice 2



Lets cut straight to the point: I love these lenses and I loved using them with the Venice 2.

I guess I had some concerns at first over choosing the Tokina Vista’s. Lets face it, Tokina are not the first brand that springs into most peoples minds when you are thinking about high quality PL cinema lenses. But I had been hearing nothing other than good things about them and when I had played with them at a couple of different trade shows, they did always look nice.

There are currently 8 lenses in the Vista range starting at the very wide 18mm and going up to 135mm. All are t1.5, are beautifully constructed with all metal bodies. The focus and aperture rings (with approx 300 degrees of travel) are in the same position on every lens in the set, so lens swaps are easy. The 9 bladed iris works well to give pleasing smooth bokeh.

DSC_0299-600x450 A Review of the Tokina Vista Prime Lenses
The Tokina Vista 135mm t1.5 on a Venice 2

 

Many manufacturers claim that their lenses have minimal breathing and this is definitely true of the Tokina Vista. Focussing from near to far resulted in only a very small change of the image size on all the lenses I tried. The breathing is truly minimal.

As I was shooting using the Venice 2’s 8.2K 17:9 mode this was a good test of the lenses resolution and sharpness. In the video at the bottom of the page you will see a couple of shots where I added a slow post production zoom in to the image, reaching 2x magnification. If you watch the video in 4K you won’t see any appreciable drop in image quality during the zoom in where I am in effect expanding the original 8.2K pixel image by 200%. This to me is a clear indication that these lenses are plenty good enough for 8K capture.

wide-shot-2_1.2.4 A Review of the Tokina Vista Prime Lenses
Wide shot, taken at 8.2K with the 18mm Tokina Vista.
mid-shot-2a_1.2.2 A Review of the Tokina Vista Prime Lenses
A crop from the frame above. Even in 4K this image looks great.

 

But, at the same time I also felt that the lenses were not excessively sharp. There is a “roundness” to the images from these lenses that I really like. The Vista’s are also very slightly warm looking and this combined with the roundness of the image and very slight propensity to flare a little gives them a very appealing look. I guess I could describe it as a vintage look, but that might make them sound old fashioned. These are not old fashioned lenses, these are clearly modern, high performance lenses. But the images they deliver has a beautiful, almost old school look that I found to be very appealing.

wide-shot-1_1.6.2 A Review of the Tokina Vista Prime Lenses
The Tokina Vistas and Venice 2 deliver great colours and skin tones.
Mid-shot1_1.6.3 A Review of the Tokina Vista Prime Lenses
This is a crop from the above image. When you have 8.2K of pixels and a high resolution lens its very easy to reframe in post production, even when delivering in 4K.



Faces and skin tones looked really nice, of course this is a combination of both a great camera and great lenses, but the colour reproduction from the combination of Venice 2 and the Tokina Vistas was very pleasing.

night-singer_1.30.2 A Review of the Tokina Vista Prime Lenses
At t1.5 the Tokina Vista’s are great for low light and Venice at 3200 ISO looks great.


I did have a play with most of the lenses in the set and they all appeared to perform similarly. But for the video shoot in London I focussed on the 18mm, 40mm and 135mm lenses. 

The 18mm is very wide. It is not truly rectilinear, there is some barrel distortion, but nothing too severe. You do have to remember that this is a t1.5 lens and it’s not easy to produce very fast, very wide lenses for full frame. The 46.7mm image circle of all the Vista lenses means that they comfortably cover the full frame Venice sensor and even at 18mm there is barely any light fall off or vignetting at the edges of the frame.

One of the other things that really impressed me with all the Vista’s was the lack of chromatic aberration. Even when shooting very high contrast, backlit edges or specular reflections it was hard to spot any chromatic aberration. There is not a single shot amongst all of the material that I shot where I noticed anything nasty.

Trafalgar-day_1.27.1 A Review of the Tokina Vista Prime Lenses
Trafalgar Square, shot with the 18mm Vista. You can see that there is some barrel distortion, but it’s pretty good for an 18mm t1.5 lens.

 

The only negative I can really find about the 18mm is the size and bulk. This is a big and heavy lens. All the Vista have the same external diameter of 114mm. The 18mm is no different in that regard. But the 18mm is one of the longest lenses in the set, it’s 180mm from front to back. And it weighs almost 2.7Kg. A big part of the weight probably comes from the bulbous front element of the lens – which you will be glad to know does not protrude beyond the end of the lens housing, giving it some protection from accidental damage.

When you have an 8K camera, wide angle lenses can be used to capture a very wide frame that can then be cropped into to re-frame in post, so having that maximum t1.5 aperture which helps maintain a shallow DoF is important. 

lanterns1_1.8.2 A Review of the Tokina Vista Prime Lenses
London’s China Town, shot with the 40mm Tokina Vista



The 40mm lens is also really nice. 40mm is an interesting focal length, a shade longer than 35mm and wider than 50mm. I found it to be a very nice focal length for a lot of different types of shots with the Venice Full Frame sensor.  At 2.24kg it is a much lighter lens than the 18mm and a fair bit shorter at 160mm. Once again extremely small amount of breathing and near total lack of chromatic aberrations makes this a lovely lens to shoot with. When shooting high contrast point light sources such as street lights at night there is a bit of circular flare around the light source, but I find this to be quite pleasing. Strong light sources just out of frame can lead to some minor veiling flare on all the lenses in the set, but this is no worse than seen with most other similar quality lenses and the lens coatings give the flare a slight warmth that again, I find very appealing.

tower-bridge_1.3.2 A Review of the Tokina Vista Prime Lenses

The 135mm lens doesn’t disappoint either, shooting at 135mm and t1.5 delivers a very narrow depth of field.  As expected this is one of the larger lenses in the set. It’s 187mm long so a bit shorter than the 18mm but it is heavier with the PL mount version coming in very close to 3kg. There isn’t much more I can say about this lens that I haven’t covered with the other lenses, extremely minimal breathing, near zero chromatic aberration etc all make for a great image. The consistent look across all the lenses means this too shares that well rounded not too clinical and very slight warmth that makes these all of these lenses very appealing.

night-busses_1.31.1 A Review of the Tokina Vista Prime Lenses
Tokina Vista 40mm on Venice 2 at 3200 ISO. I really like the way the Vistas flare.



The Tokina Vista’s are not re-housed photo lenses, they were designed specifically for digital cinematography. They are available in a range of mounts including PL, Canon EF, MFT, LPL and Sony E. I had heard good things about them from other users before I tried them and now I have had a chance to shoot with them I have to say that they are lenses that I will want to use again. Perhaps in particular when the project would benefit from a slight vintage or romantic look without being soft and without giving up any resolution. For the money they are great looking lenses and would recommend anyone that hasn’t tried them to give them a go.

More Anamorphic Options for the FX9 – Sirui 24mm 1.33x Anamorphic.

Here is what could be a nice option for Anamorphic on the FX9 (or any other Super 35mm capable camera. The new Sirui 24mm 1.33x anamorphic lens. I have not tried these yet, but at only $999 or $749 with the early bird offer it’s certainly an affordable way into the world of Anamorphic. 1.33x lenses are designed to provide a final aspect ratio of 2.40:1 when used with a 16:9 sensor. Here’s the info from the press release.

large-e5f243596bfbebfadb05d80a1c0e418d More Anamorphic Options for the FX9 - Sirui 24mm 1.33x Anamorphic.
large-a0779796aff6c0276f70ae6b5c0c2ecc More Anamorphic Options for the FX9 - Sirui 24mm 1.33x Anamorphic.
large-dc99f9fef16c45ad702d8d811aff5cd7 More Anamorphic Options for the FX9 - Sirui 24mm 1.33x Anamorphic.
The SIRUI 1.33x Anamorphic line-up consists of 24mm, 35mm and 50mm lenses.
  • Focal length: 24mm
  • Maximum aperture: F2.8
  • Minimum aperture: F16
  • Lens structure: 13 elements in 10 groups
  • Aperture blades: 8
  • Maximum support frame: APS-C
  • Shooting distance: 0.6m (2 ft) – infinity
  • Focus method: Manual focusing
  • Maximum magnification: 1:21.99(V),1:29.07 (H)
  • Filter spec: M72 x 0.75
  • Rotation angle of the focus ring: 189.6°
  • Max. diameter: 74mm (2.91 inches)
  • Diameter of focus ring: 64.6mm (2.54 inches)
  • Weight(g/lbs): MFT Mount: 770/1.70; E Mount: 780/1.72; X Mount: 780/1.72; EF-M Mount: 780/1.72; Z Mount: 810/1.79
  • Total length (lens cap not included) (mm/inch): MFT Mount: 124.9/4,92; E Mount: 126.1/4.96; X Mount: 126.4/4.98; EF-M Mount: 126.1/4.96; Z Mount: 128.1/5.04
preview-eb0cf788bc1720d61f3bb2319c6421ab More Anamorphic Options for the FX9 - Sirui 24mm 1.33x Anamorphic.

Guess The Lens! A little bit of fun and an interesting test.

Last week I was at O-Video in Bucharest preparing for a workshop the following day. They are a full service dealer. We had an FX9 for the workshop and they had some very nice lenses. So with their help I decided to do a very quick comparison of the lenses we had. I was actually very surprised by the results. At the end of the day I definitely had a favourite lens. But I’m not going to tell you which one yet.

The 5 lenses we tested were: Rokinon Xeen, Cooke Panchro 50mm, Leitz (lecia) Thalia, Zeiss Supreme Radiance and the Sony 28-135mm zoom that can be purchased as part of a kit with the FX9.

I included a strong backlight in the shot to see how the different lenses dealt with flare from off-axis lights. 2 of the lenses produced very pronounced flare, so for those lenses you will see two frame grabs. One with the flare and one with the back light flagged off.

I used S-Cinetone on the FX9 and set the aperture to f2.8 for all of the lenses except the Sony 28-135mm. For that lens I added 6dB of gain to normalise the exposure, you should be able to figure out which of the examples is the Sony zoom.

One of the lenses was an odd focal length compared to all the others. Some of you might be able to work out which one that is, but again I’m not going to tell you just yet.

Anyway, enjoy playing guess the lens. This isn’t intended to be an in depth test. But it’s interesting to compare lenses when you have access to them.  I’ll reveal which lens is which in a couple of weeks in the comments. You can click on each image to enlarge it.

Big thanks to everyone at O-Video Bucharest for making this happen.

Lens1-flare Guess The Lens! A little bit of fun and an interesting test.
Lens 1 with flare from backlight.
lens1-no-flare Guess The Lens! A little bit of fun and an interesting test.
Lens 1 with backlight flagged to reduce the flare.
lens2 Guess The Lens! A little bit of fun and an interesting test.
Lens 2
lens-3 Guess The Lens! A little bit of fun and an interesting test.
Lens 3
lens-4-no-flare Guess The Lens! A little bit of fun and an interesting test.
Lens 4
lens-5-flare Guess The Lens! A little bit of fun and an interesting test.
Lens 5 with flare from backlight
lens-5-No-flare Guess The Lens! A little bit of fun and an interesting test.
Lens 5 with backlight masked to kill the flare.

Which Lenses work well with the FX9’s Autofocus?

Below is a list of lenses that have been tested with the FX9’s advanced autofocus system. Generally any Sony E-mount lens will work just fine. The Sony G series lenses are good and the G Master series tend to be even better. 
For third party lenses and adapters the situation is much less clear, so I have decided to list the lenses I have tested and invite others to contribute to this list via the comments area. The list is not exhaustive at this time but I will try to keep adding to it as I am able to try more lenses and and different adapter combinations.

Inclusion of a lens on this list is not a guarantee that it will or will not work, it is simply an indication of how it worked for me or anyone else that adds information about their own experiences. I welcome updates and any further information from any lens or adapter manufacturer.

If there is a lens you have tested on an FX9 please let me know via the comments how it worked so it can be added to the list.

KNOWN TO WORK WELL:

Sony E (super 35mm) FE (full frame) lenses, G and G-Master including Zeiss ZA series. G and G Master  tend to have the best AF performance.

Tamron 28-75 f2.8 Di III RXD E-mount.

KNOWN TO WORK, BUT NOT AS GOOD AS ORIGINAL SONY:

Sigma 20mm f1.4 ART with Sigma MC11 adapter. Works, but a little slow and occasionally hunts.

KNOWN TO NOT PERFORM WELL:

Sigma 20mm f1.4 ART native E-mount (very slow AF, hunting, contrast only?).

Sigma 85mm f1.4 ART native E-mount (very slow AF, a lot of hunting).

Sigma 20mm f1.4 ART Canon EF mount on metabones, comlite or viltrox adapters. Very slow AF, not really useable.

NO GOOD, NO AF:

Tamron EF 16-300mm

Sigma EF 18-250mm

 

The “E” in “E-Mount” stands for Eighteen.

A completely useless bit of trivia for you is that the “E” in E-mount stands for eighteen. 18mm is the E-mount flange back distance. That’s the distance between the sensor and the face of the lens mount. The fact the e-mount is only 18mm while most other DSLR systems have a flange back distance of around 40mm means thare are 20mm or more in hand that can be used for adapters to go between the camera body and 3rd party lenses with different mounts.

Here’s a little table of some common flange back distances:

MOUNT FLANGE BACK SPARE/Difference
e-mount 18mm
Sony FZ (F3/F5/F55) 19mm 1mm
Canon EF 44mm 26mm
Nikon F Mount 46.5mm 28.5mm
PL 52mm 34mm
Arri LPL 44mm 26mm
Sony A, Minolta 44.5mm 26.5mm
M42 45.46mm 27.46mm

Thinking about new lenses for the FX9?

DSC_0421-2-1024x576 Thinking about new lenses for the FX9?
Sony 28-135mm f4 zoom on the PXW-FX9

If you are starting to think about lenses to take advantage of the FX9’s amazing autofocus capabilities then you should know that I have tested quite a few different lenses on the FX9 now. I have yet to find a Sony lens where the AF hasn’t worked really well. Even the low cost Sony 50mm f1.8 and 28mm f2 lenses worked very well. Infact I actually quite like both of these lenses and they represent great value for the money.

But what I have found is that non Sony lenses have not worked well. I have been testing a range of lenses on various pre-production cameras. Maybe this situation will improve through firmware updates, I would hope so, but I honestly don’t know. The E-mount Sigma 18-35 and 20mm art lenses I tried were not at all satisfactory. The AF worked, but in what appears to be a contrast only mode. The autofocus was much slower and hunted compared to the fast, hunt free AF with the Sony lenses. You would not want to use this which is a great shame as these lenses are optically very nice.

It’s the same story when using Canon EF lenses via both Metabones and Viltrox adapters (I have not tested the Sigma MC11). Phase AF does not appear to work, only contrast and it’s slow.

So if you are thinking about buying lenses for the FX9 the only lenses I can recommend right now are Sony lenses. Don’t (at this stage at least) buy other brand E-mount lenses or expect lenses to be used via adapters unless you can find a way to test them on an FX9 first.

Shooting Anamorphic with the Fujinon MK’s and SLR Magic 65 Anamorphot.

There is something very special about the way anamorphic images look, something that’s not easy to replicate in post production. Sure you can shoot in 16:9 or 17:9 and crop down to the typical 2.35:1 aspect ratio and sure you can add some extra anamorphic style flares in post. But what is much more difficult to replicate is all the other distortions and the oval bokeh that are typical of an anamorphic lens.

Anamorphic lenses work by distorting the captured image. Squeezing or compressing it horizontally, stretching it vertically. The amount of squeeze that you will want to use will depend on the aspect ratio of the sensor or film frame. With full frame 35mm cameras or cameras with a 4:3 aspect ratio sensor or gate you would normally use an anamorphic lens that squeezes the image by 2 times. Most anamorphic cinema lenses are 2x anamorphic, that is the image is squeezed 2x horizontally. You can use these on cameras with a 16:9 or 17:9 super35mm sensor, but because a Super35 sensor already has a wide aspect ratio a 2x squeeze is much more than you need for that typical cinema style final aspect ratios of 2.39:1.

For most Super35mm cameras it is normally better to use a lens with a 1.33x squeeze. 1.33x squeeze on Super35 results in a final aspect ratio close to the classic cinema aspect ratio of 2.39:1.

Traditionally anamorphic lenses have been very expensive. The complex shape of the anamorphic lens elements are much harder to make than a normal spherical lens. However another option is to use an anamorphic adapter on the front of an existing lens to turn it into an anamorphic lens. SLR Magic who specialise in niche lenses and adapters have had a 50mm diameter 1.33x anamorphic adapter available for some time. I’ve used this with the FS7 and other cameras in the past, but the 50mm diameter of the adapter limits the range of lenses it can be used with (There is also a 50mm 2x anamorphot for full frame 4:3 aspect ratio sensors from SLR Magic).

Now SLR Magic have a new larger 65mm adapter. The 1.33-65 Anamorphot has a much larger lens element, so it can be used with a much wider range of lenses. In addition it has a calibrated focus scale on it’s focus ring. One thing to be aware of with adapters like these is that you have to focus both the adapter and the lens you are using it on. For simple shoots this isn’t too much of a problem. But if you are moving the camera a lot or the subject is moving around a lot, trying to focus both lenses together can be a challenge.

DSC_0103 Shooting Anamorphic with the Fujinon MK's and SLR Magic 65 Anamorphot.
The SLR Magic 1.33-65 Anamorphot anamorphic adapter.

Enter the PD Movie Dual Channel follow focus.

The PD Movie Dual follow focus is a motorised follow focus system that can control 2 focus motors at the same time. You can get both wired and wireless versions depending on your needs and budget. For the anamorphic shoot I had the wired version (I do personally own a single channel PD Movie wireless follow focus). Setup is quick and easy, you simply attach the motors to your rods, position the gears so they engage with the gear rings on the lens and the anamorphot and press a button to calibrate each motor. It takes just a few moments and then you are ready to go. Now when you turn the PD Movie focus control wheel both the taking lens and the anamorphot focus together.

I used the anamorphot on both the Fujinon MK18-55mm and the MK50-135mm. It works well with both lenses but you can’t use focal lengths wider than around 35mm without the adapter some causing vignetting. So on the 18-55 you can only really use around 35 to 55mm. I would note that the adapter does act a little like a wide angle converter, so even at 35mm the field of view is pretty wide. I certainly didn’t feel that I was only ever shooting at long focal lenghts.

DSC_0099 Shooting Anamorphic with the Fujinon MK's and SLR Magic 65 Anamorphot.
The full rig. PMW-F5 with R5 raw recorder. Fujinon MK 18-55 lens, SLR Magic Anamorphot and PD Movie dual focus system.

Like a lot of lens adapters there are some things to consider. You are putting a lot of extra glass in front of you main lens, so it will need some support. SLR magic do a nice support bracket for 15mm rods and this is actually essential as it stops the adapter from rotating and keeps it correctly oriented so that your anamorphic squeeze remains horizontal at all times. Also if you try to use too large an aperture the adapter will soften the image. I found that it worked best between f8 and f11, but it was possible to shoot at f5.6. If you go wider than this, away from the very center of the frame you get quite a lot of softening image softening. This might work for some projects where you really want to draw the viewer to the center of the frame or if you want a very stylised look, but it didn’t suit this particular project.

The out of focus bokeh has a distinct anamorphic shape, look and feel. As you pull focus the shape of the bokeh changes horizontally, this is one of the key things that makes anamorphic content look different to spherical. As the adapter only squeezes by 1.33 this is as pronounced as it would be if you shot with a 2x anamorphic. Of course the other thing most people notice about anamorphic images is lens flares that streak horizontally across the image. Intense light sources just off frame would produce blue/purple streaks across the image. If you introduce very small point light sources into the shot you will get a similar horizontal flare. If flares are your thing it works best if you have a very dark background. Overall the lens didn’t flare excessively, so my shots are not full of flares like a JJ Abrams movie. But when it did flare the effect is very pleasing. Watch the video linked above and judge for yourself.

Monitoring and De-Squeeze.

When you shoot anamorphic you normally record the horizontally squashed image and then in post production you de-squeeze the image by compressing it vertically. Squashing the image vertically results in a letterbox, wide screen style image and it’s called “De-Squeeze”. You can shoot anamorphic without de-sqeezing the image provided you don’t mind looking at images that are horizontally squashed in your viewfinder or on your monitor. But these days you have plenty of monitors and viewfinders that can “de-squeeze” the anamorphic image so that you can view it with the correct aspect ratio. The Glass Hub film was shot using a Sony PMW-F5 recording to the R5 raw recorder. The PMW-F5 has the ability to de-squeeze the image for the viewfinder built in. But I also used an Atomos Shogun Inferno to monitor as I was going to be producing HDR versions of the film. The Shogun Inferno has both 2x and 1.33x de-squeeze built in so I was able to take the distorted S-Log3 output from the camera and convert it to a HDR PQ image and de-squeeze it all at the same time in the Inferno. This made monitoring really easy and effective.

I used DaVinci Resolve for the post production. In the past I might have done my editing in Adobe Premiere and the grading in Resolve. But Resolve is now a very capable edit package, so I completed the project entirely in Resolve. I used the ACES colour managed workflow as ACES means I don’t need to worry about LUT’s and in addition ACES adds a really nice film like highlight roll off to the output. If you have never tried a colour managed workflow for log or raw material you really should!

The SLR Magic 65-1.33 paired with the Fujinon MK lenses provides a relatively low cost entry into the world of anamorphic shooting. You can shoot anywhere from around 30-35mm to 135mm. The PD Movie dual motor focus system means that there is no need to try to use both hands to focus both the anamorphot and the lens together. The anamorphot + lens behave much more like a quality dedicated anamorphic zoom lens, but at a fraction of the cost. While I wouldn’t use it to shoot everything the Anamorphot is a really useful tool for those times you want something different.

Sigma FF High Speed Primes.

The main lenses I used for my recent Sony Venice shoot in Arizona were the  Sigma Full Frame High Speed primes in PL mount.

These are really really nice lenses!

20180418_110628-1024x576 Sigma FF High Speed Primes.
Sigma Full Frame fast prime lens set.

As they cover a full frame sensor such as the one in Sony’s Venice high end digital cinematography camera these are pretty future proof lenses. They are all fast lenses with most of them opening up to T1.5. At T1.5 you have a 20, 24, 35, 50 and 85mm lenses and at T2.0 you can go as wide as 14mm and as long as 135mm.

They are of all metal construction, the build quality is absolutely first class. As soon as you pick one up it just exudes quality. They are not light weight lenses, coming in at between 1kg and 1.3kg in PL mount form, but that weight gives you the confidence that these are lenses that will last. Lenses that will stand up to daily professional use on a film or documentary shoot.  They are dust and moisture sealed, which is probably just as well as on this shoot there was a lot of blowing sand and dust. Our on set photographer was having problems with sand and grit in his lenses by the end of the shoot, but the Sigmas just shrugged it off.

The focus and aperture markings are very clear and easy to read they even glow in the dark! The focus ring rotates through a full 180 degrees and both the focus and aperture rings have standard 0.8 pitch teeth for follow focus controls etc. The gear rings are all the same distance from the mount so there is no need to move the follow focus when changing lenses.

20180418_110645-1024x576 Sigma FF High Speed Primes.
Sigma 85mm Full Frame High Speed prime.

The lenses are available with PL, E mount or EF mounts. The set I had were fitted with PL. The mounts are not user interchangeable, but you can have the mount swapped by Sigma if you do find that you need to change it for some reason.

I shot several scenes with the 20mm lens using the Venice’s full frame 6K x 4K mode. Examining these images in post production reveals that the 20mm is really sharp right out into the corners. I also shot with the lenses wide open in some pretty dark places and even wide open they stay tack sharp. Take a look at the image below, it’s really sharp. If you click on the image you can enlarge it to view it at close to the original 6K resolution.

Horseshoe-bend_1.1.6-1024x576 Sigma FF High Speed Primes.
Frame grab from Venice. Horseshoe bend, Page Arizona. Sigma 20mm FF prime. Click on the image to enlarge.

Shooting night scenes with the 135mm wide open also gave beautiful results. When shooting with a shallow DoF all the lenses have a very pleasing bokeh. This is perhaps in part thanks to the use in all of the lenses of a 9 blade, rounded diaphragm aperture system.

When changing focus mid shot breathing is minimal and the focus ring is silky smooth. A really nice touch is the use of a damper at the focus stops so there is no noise if you hit the end stops.

Vegas-night2_1.1.2-1024x576 Sigma FF High Speed Primes.
Frame Grab from Venice, 2500 ISO, Sigma 24mm. Click on the image to expand.

During the shoot I used the 20,24,35,50,85 and 135mm lenses and they all performed really well. Looking at the footage in the grading suite it looks sharp and there are no nasty distortions. I did notice a touch of barrel distortion with the 24mm but this is to be expected with a wide lens on a full frame sensor. All the lenses matched really well, the colour remaining constant throughout the whole range. The look from the lenses was very neutral. Lens flare was extremely well controlled and I didn’t notice my blacks becoming washed out in high contrast situations. When shooting into the sun or at a direct light source any flare that I did see was normally quite pleasing.

The shot below was obtained shooting towards the sun when it was very low in the sky, yet the lens behaved flawlessly retaining deep blacks and a very high contrast image.

horse-riding_1.1.14-1024x576 Sigma FF High Speed Primes.
Frame grab from Venice with Sigma 135mm FF lens shooting into the sun in a very high contrast scenario. Click on the image to enlarge.

These lenses helped me capture some truly beautiful images with the Venice camera. I’ve long been a fan of Sigmas more recent lens designs. I have several of the Sigma Art Lenses and these have always performed exceptionally well. These prime lenses take things one step further putting world class optics into housings designed for manual control and the rigours of professional film and video productions. They are very competitively priced, especially when you consider that these are full frame lenses. I really hope to be able to use them again on future shoots. They really are top notch lenses and the images I captured with them look gorgeous.

 

Low Light Performance – It’s all about the lens!

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.

The Dangers Of Hidden Moisture.

Electronics and water are two things that just don’t match. We all know this and we all know that dropping a camera into a river or the sea probably isn’t going to do it a great deal of good. But one of the very real risks with any piece of electronics is hidden moisture, moisture you can’t see.

Most modern high definition or 4K pro video cameras have fans and cooling systems designed to keep them operating for long periods. But these cooling systems mean that the camera will be drawing in air from the outside world into the cameras interior. Normally this is perfectly fine, but if you are operating in rain or a very wet environment such as high humidity, spray, mist, fog etc it will mean a lot of moisture circulating through the camera and this can be a cause of problems.

If the camera is warm relative to the ambient temperature then generally humid air will simply pass through the camera (or other electronics) without issue. But if the camera is colder than the airs dewpoint then some of the moisture in the air will condense on the cameras parts and turn into water droplets.

A typical dangerous scenario is having the camera in a nice cool air conditioned car or building and then taking the camera out of the car/building to shoot on a warm day.  As the warm air hits the slightly colder camera parts moisture will form, both on the outside and the inside of the cameras body.

Moisture on the outside of the camera is normally obvious. It also tends to dry off quite quickly, but moisture inside the camera can’t be seen, you have no way of knowing whether it’s there or not. If you only use the camera for a short period the moisture won’t dry out and once the fans shut down the cameras interior is no longer ventilated and the moisture stays trapped inside.

Another damaging scenario is a camera that’s been splashed with water, maybe you got caught in an unexpected rain shower. Water will find it’s way into the smallest of holes and gaps through capillary action. A teeny, tiny droplet of water inside the camera will stay there once it gets inside. Get the camera wet a couple of times and that moisture can start to build up and it really doesn’t take a lot to do some serious damage. Many of the components in modern cameras are the size of pin heads. Rain water, sea water etc contain chemicals that can react with the materials used in a cameras construction, especially if electricity is passing through the components or the water and before you know it the camera stops working due to corrosion from water ingress.

Storing you delicate electronics inside a nice waterproof flight case such as a Pelicase (or any other similar brand) might seem like a good idea as these cases are waterproof. But a case that won’t let water in also won’t let water and moisture out. Put a camera that is damp inside a wateproof case and it will stay damp. It will never dry out.  All that moisture is gong to slowly start eating away at the metals used in a lightweight camera body and some of the delicate electronic components. Over time this gets worse and worse until eventually the camera stops working.

So What Should You Do?

Try to avoid getting the camera wet. Always use a rain cover if you are using a camera in the rain, near the sea or in misty, foggy weather. Just because you can’t see water flowing off your camera it doesn’t mean it’s safe. Try to avoid taking a cold camera from inside an air conditioned office or car into a warmer environment. If you need to do this a lot consider putting the camera in a waterproof bag ( a bin bag will do) before taking the camera into the warmer environment. Then allow the camera to warm up in the bag before you start to use it. If driving around in a car from location to location consider using less air conditioning so the car isn’t so cold inside.

Don’t store or put away a damp camera. Always, always throughly dry out any camera before putting it away. Consider warming it up and drying it with a hairdryer on a gentle/low heat setting (never let the camera get too hot to handle). Blow warm dry air gently into any vents to ensure the warm air circulates inside to remove any internal moisture. Leave the camera overnight in a warm, dry place with any flaps or covers open to allow it to dry out throughly.

If you know you camera is wet then turn it off. Remove the battery and leave it to dry out in a warm place for 24 hours. If it got really wet consider taking it to a dealer or engineer to have it opened up to make sure it’s dry inside before adding any power.

If you store your kit in waterproof cases, leave the lids open to allow air to circulate and prevent moisture building up inside the cases. Use Silica Gel sachets inside the cases to absorb any unwanted moisture.

If you live or work in a warm humid part of the world it’s tough. When I go storm chasing going from inside the car to outside in the warm to shoot is not healthy for the camera. So at the end of each day take extra care to make sure the camera is dry. Not just any obvious moisture on the outside but dry on the inside. So this normally means warming it up a little (not hot, just warm). Again a hair drier is useful or leave the camera powered up for a couple of hours in an air conditioned room (good quality aircon should mean the air in the room is dry). I keep silica gel sachets in my camera bags to help absorb any surplus moisture. Silica gel sachets should be baked in an oven periodically to dry them out and refresh them.

Fogged Up Lens?

Another symptom of unwanted moisture is a fogged up lens. If the lens is fogged up then there will almost certainly be moisture elsewhere. In the case of a fogged up lens one thing that sometimes helps (other than a hairdryer) is to zoom in and out a lot if it’s a zoom or change the focus a lot. Moving the lens elements backwards and forwards inside the lens helps to circulate air inside the lens and can speed up the time it takes to dry out.