Tag Archives: lens

The new Sony FS7 zoom lens, the Sony SELP18110G.

AJC03714-1024x681 The new Sony FS7 zoom lens, the Sony SELP18110G.
Sony SELP18110G servo zoom lens.

When Sony launched the FS7 II they also launched a new lens to go along with it. The previous zoom lens that was bundled with the FS7 was the SELP28135G, a 28-135mm f4 zoom lens that would work with Super 35mm, APS-C and full frame cameras. While generally well received this lens is not without it’s problems. For a start it’s not really wide enough for use as a general purpose lens on an APS-C or Super 35mm sensor. The other problem is that the zoom is very slow. Even when set to manual zooming in and out takes a long time. You turn the zoom ring and then have to wait for the lens to catch up.

The new lens is a wider 18mm to 110mm f4 lens. This is a really useful zoom range for a Super 35mm camera. But the new lens can only be used on S35mm and APS-C cameras. It can’t be used with full frame cameras like the A7s in full frame mode.

AJC03718-1024x681 The new Sony FS7 zoom lens, the Sony SELP18110G.
The front element of the Sony SELP18110G.

But what about the zoom speed? Well this has been addressed too. On the 28-135mm lens the zoom function is electronic. There is no mechanical connection between the zoom ring and the optics of the lens. The 18-110 has a proper mechanical connection between the zoom ring and the internal lenses, so now you can crash zoom in and out as fast as you want. In addition the zoom servo motor is much faster and motorised zooms take place much more rapidly. One downside to this is that it’s a bit harder to control the zoom speed. You can do slow creeping zooms if you are very careful with the cameras zoom rocker, but it’s hard to do. The difference in pressure on the zoom rocker between creeping zoom and medium speed is tiny. The lens tended to change zoom speed quite quickly. While it is indeed very nice to have a variable speed motorised zoom, don’t expect the fine degree of control that you get from admittedly more expensive traditional ENG lenses. Lets face it this lens is only around £3K/$5K which is remarkable cheap for a parfocal s35mm zoom. Take a look at the video below for an idea of the zoom speeds etc.

Is it really parfocal? Well yes, it does seem to be parfocal. I only had the lens for a morning to play with, but in all my tests the focus remained constant throughout the zoom range.

So, what about focus? Like the 28-135mm lens there is a nice big focus ring that slides fore and aft.

AJC03723-e1487017741838 The new Sony FS7 zoom lens, the Sony SELP18110G.
Focus, zoom and iris rings on the SELP18110G.

In the rear position the focus is manual and there are calibrated focus markings and end stops. You get about 180 degrees of focus travel from 0.95m (3.1ft) to infinity (in autofocus you can focus slightly closer when the lens is at the wide end). The focus ring has 0.8mm pitch teeth for use with most standard follow focus units, although this gear ring is very close to the end of the lens, so it may be tricky to use if you have a matte box in place. Breathing is very well controlled and barely noticeable unless going through very large focus throws. Out of focus Bokeh isn’t bad either, I didn’t observe any nasty surprises in the limited time I had to play with the lens.

Bokeh-1024x576 The new Sony FS7 zoom lens, the Sony SELP18110G.
Frame Grab. Near and far out of focus bokeh is reasonable on the Sony SELP18110G. Click on the image to view a full size copy.

Sharpness and flare. The lens appears to be nice and sharp at the wide end but just a touch soft at the long end. It’s not bad overall but when shooting at 4K I could just about detect the lens becoming marginally softer as I zoomed in. The sample I had was a well used pre-production prototype, but I’m going to guess that the production lenses won’t be hugely different. Shooting the roof of a house against a bright sky revealed only a small amount of flare, certainly nothing out of the unusual for a zoom lens.

18110-110-1024x576 The new Sony FS7 zoom lens, the Sony SELP18110G.
Frame grab from the Sony SELP18110G at 110mm. Click on the image to view a full size copy.
18110-18-1024x576 The new Sony FS7 zoom lens, the Sony SELP18110G.
Frame grab shot with Sony SELP18110G at 18mm. Click on the image to view the full size image.

Overall I really like this lens. It even has a support point at the front of the lens body for additional stability. While f4 isn’t the largest of apertures it is quite usable and even wide open the lens performs well. For the money it is a lot of lens. I think we need to be realistic with our expectations for zoom lenses and large sensors. Bigger zoom ratios require bigger lens elements if we want to maintain a constant aperture. Bigger lens elements cost more to produce.

AJC03729-e1487018834354 The new Sony FS7 zoom lens, the Sony SELP18110G.
Underside of the Sony SELP18110G showing the extra lens support points. A lens foot that attaches to the rear mounting is included with the lens.

One advantage Sony have over the competition is that it’s easier to make zoom lenses for the very short flange back distance of the E-Mount cameras compared to the deeper flange back of PL or Canon mounts. The closest competition to this lens is the Canon 18-80mm T4.4 (f4 ish) which is a fair bit more expensive (£4K/$6K). If you want a similar zoom range then you’re looking at the beautiful  Fujinon 20-120 T3.4 at around £14K/$19K.

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Image quality with B4 ENG lenses on large sensor cameras.

DSC02056 Image quality with B4 ENG lenses on large sensor cameras.
2/3″ B4 lens on the FS700via the MTF adapter.

This is something that comes up a lot and I get many questions about. In part because I designed the MTF B4 to Canon, FZ and E-Mount adapters. Budget adapters that allow you to use a 2/3″ B4 ENG lens on a Super 35mm sensor by using the lenses 2x extender or on a center crop sensor without the 2x.

The question is… what will the pictures look like?

The answer is… it depends on the lens.

Not a very helpful answer perhaps, but that’s the truth of it. Different lenses perform very differently. For a start I would say forget 4K. At best these lenses are suitable for HD and you want to have a great HD lens if you want good HD pictures.

But what about the “look” of the images? My experience is that if you put a wide range ENG zoom on a S35mm camera the look that you get can be best described as “2/3″ ENG look with maybe shallow depth of field”. Lets face it, ENG lenses are full of compromises. To get those great big zoom ranges with par-focal focus there are a lot of glass elements in those lenses. Lot’s of elements means lots of places where CA and flare can occur. The end result is often a lowering of contrast and color fringing on hard edges, the very same look that we are used to seeing on 2/3″ cameras.  Typical cine or DSLR lenses tend to have simpler optical designs. Prime lenses are normally sharper and show better contrast with less flare than zooms due to there simpler internal design.

So don’t expect to put a typical B4 ENG lens on your S35mm camcorder and still have that crisp, high contrast digital cinema look. Of course B4 zooms are handy for the ability to zoom in and out through huge ranges while holding focus. So an adapter and lens may well make your S35mm camera more versatile. But if you want the best possible images stick to cine style lenses, DSLR lenses or zooms designed for S35.

 

News From NAB 2016 – Firmware Update for 18-105mm Lens.

Sony have released a firmware update for the 18-105mm lens that is available as a package with the FS5. The update addresses some of the focus tracking issues that some lenses appear to have. To update the lens firmware you need to go to the support page of Sony consumer:  http://www.sony.co.uk/support/en/product/SELP18105G

and download the update package. You will need to have the lens mounted on a camera and the camera connected to a Mac or PC. Full install instructions are provided after you click on the Mac or PC download link buttons.

Metabones FZ to Canon Mount.

20150910_095809-1024x576 Metabones FZ to Canon Mount.
Metabones Sony FZ to Canon EF adapter.

There was one of these at IBC last year. A new version appeared again this year at IBC and it’s really nice. I so hope that this becomes a real product. It fits the Sony PMW-F5 and PMW-F55 cameras (and I must assume the PMW-F3 too). It takes it’s power from the camera and will control a Canon EF lens. Aperture is controlled by a large aperture ring which has clear aperture marking visible at the side of the adapter. No fiddly knobs or dials, no power cable and a real aperture scale. In addition I believe you will get an aperture display in the viewfinder. The EF Lens mount features a large locking ring so the lens won’t twist or rotate once mounted, something essential if you are going to use a follow focus. This version was much nicer than the one shown last year. I really hope it becomes a real product as I’d like one for my F5.

20150910_095827-1024x576 Metabones FZ to Canon Mount.
Metabones FZ to Canon EF adapter showing the locking mount system.

Samyang launches 50mm Cine Lens

50mm-vdslr-front-226x300 Samyang launches 50mm Cine Lens
New Samyang 50mm T1.5 vDSLR lens.

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.

 

Scheider Xenon FF Prime Lenses.

DSC_0034-1024x576 Scheider Xenon FF Prime Lenses.
Schneider Xenon 50mm FF lens on the Sony A7s

When you think of cine lenses then there are several brands that immediately come to mind. Zeiss, Arri, Cooke and Angenieux are probably the most familiar names but there are many others too. One brand I have been looking at more and more recently is Schneider.
Schneider Kreuznach have been making lenses since 1913. Based in Kreuznach in Germany they have long been know for their innovative designs and they won an Oscar in 2001 for Technical Achievement for their Super-Cinelux motion picture lenses.
A few years ago I met one of their lens engineers at NAB. I don’t think I have ever met a man as passionate about a lens design before or since. Every Schneider lens that I have ever used has been brilliant. They always seem to have near zero breathing, are always extremely solidly built and produce great images. So when I got a call from Manfrotto, the UK distributor to see if I would like a chance to play with some of the new Xenon FF (Full Frame) lenses I grabbed the opportunity.

DSC_0036-300x168 Scheider Xenon FF Prime Lenses.
Another view of the 50mm Schneider Xenon FF lens.

The Xenon FF lenses are cine style lenses available with either Canon, Nikon or PL mounts. The mounts can be changed should you need to switch mounts at a later date. They are priced to directly compete with the Zeiss compact primes. At the moment there are only 3 lenses available, a 35mm, 50mm and 75mm, all are T2.1. In the near future there will also be a 25mm and 100mm T2.1 as well as an 18mm T2.4 Yum Yum! I’d love to have one of those for my Northern Lights or Storm Chasing expeditions. They are all the same size, have a 100mm front diameter, all have a 95mm lens thread. This means that swapping lenses during a shoot is straight forward as you don’t have to change Matte Box donuts or re-position the follow focus if you’re using one. Being Full Frame lenses and rated for 4K these should be a great match with the Sony A7s.

I got to play with a 35mm and 50mm with EF mount and decided to try them on my full frame A7s shooting in HD as well as taking a few still photos (which are the equivalent to 4.5K) on a cloudy and rainy day.

DSC_0042-168x300 Scheider Xenon FF Prime Lenses.
14 blade iris and EF mount on the 35mm Xenon FF.

Straight out of the box you cannot help but be impressed by the build quality. These are substantial lenses, weighing in at around 1.25kg each with the EF mount. I could not find any plastic on these lenses, they look built to last.

The focus scale is large and easy to read, each lens being individually calibrated. Focus travel is a full 300 degrees. Even as you get to the far end of the focus ring the distances are still nicely spaced. From 9ft(3m) to infinity is around 100 degrees. Compare that to most DSLR lenses where the same focus range might be compressed into just  5 or 10 degrees and you can see that precise focus is much easier. Although sometimes  a very large focus travel can make focus pulls a little harder simply because or the large distance the focus ring has to be turned. But I’ll take a big focus throw lens over small throw any day.
The lenses have 14 curved iris blades giving a very round aperture even when stopped right down. I love peering into these lenses at the aperture blades as they are a work of art (but really hard to take a photo of). You can also see in the photo that the coatings of the lens are a distinct orange colour.

DSC04400-300x200 Scheider Xenon FF Prime Lenses.
Photo taken with the 50mm Xenon FF. Click on the image to enlarge or view at original resolution.

In practice the lenses did not disappoint. It did seem a bit odd to have such a large and heavy lens on the diminutive A7s, but as image quality starts with the lens a good lens can make all the difference. I shot at various apertures from wide open at T2.1 down to about T8 and didn’t notice any significant change in resolution across the range (I took photos as well as video to check the lens performance).

The lenses do tend to flare a little bit, the 35mm more than the 50mm, but I thought the flares were quite pleasing, others may disagree. Take a look at the video to get an idea of what they are like. There was a bit more flare at T2.1 compared to T2.8 or T4 on both lenses.
I did some big focus pulls to see how much breathing there was and as with all the Schneider lenses I’ve used breathing was very minimal. There is some breathing, these are not like the Cine-Xenars which have virtually zero breathing, but the breathing really is small.

Grab-thru-trees-300x168 Scheider Xenon FF Prime Lenses.
Frame grab, shooting through trees. 35mm Xenon FF and A7s.

Another test shot was to shoot some tree branches silhouetted against the sky to check for CA and colour fringing. Basically I can’t see any. Maybe right out in the very corners of the frame there is the tiniest bit of CA, but you really have to hunt for it.

Shoping-basket-grab-1024x576 Scheider Xenon FF Prime Lenses.
Shopping basket frame grab. 35mm Xenon FF. I love the smoothness to the highlights.

Colour wise there is no obvious colour shift, if anything perhaps very, very slightly warm. As expected the lenses are very sharp and crisp, from corner to corner, but not excessively so. I found that the images contained a lot of detail but had a pleasing roundness too them that I really like. I shot a chrome shopping basket and the reflections of the bright chrome look really nice. I think this is a combination of a little bit of flare without excessive sharpness. I think it’s a very nice natural look. This can be one of the benefits of a video lens over a stills lens. Stills lenses must be incredibly sharp to work with 24 or 36 mega pixel sensors. Sometimes this results is a super sharp image that lacks character. Arguably if you start with a very sharp image you can always soften it a bit in post, but sometimes it’s nice to start off with a more rounded image. Look at how popular Cooke lenses are, they are well known for their rounded rather than super sharp images.

As expected from a 14 blade iris the bokeh is very creamy and smooth. Both near and far out of focus areas look very good indeed. Out of focus edges are smooth and don’t show any obvious double edges or other distortions.

berries-grab-1024x576 Scheider Xenon FF Prime Lenses.
It’s really easy to get a very shallow DoF with a full frame sensor. Xenon FF 50mm and A7s.

Take a look at the video for a better idea of the lens flares and the overall image quality. I really like the look you get from these lenses and wouldn’t mind a set of them for myself. I feel they have a lot in common with Cooke lenses, but at a much more affordable price. I hope to test them further in the near future and to a wider variety of scenes. I suspect they will be very good on skin tones and faces.

 

Quick test of the CommLite EF to NEX lens adapter. CN-EF-NEX

commlite-300x300 Quick test of the CommLite EF to NEX lens adapter. CN-EF-NEX
Commlite full frame EF to NEX lens mount adapter.

My old Metabones MK1 adapter is not suitable for full frame lenses on the new Sony A7s. So in anticipation of the arrival of my A7s I ordered a cheap CommLite full frame autofocus ready adapter on ebay. This adapter (CN-EF-NEX) was only $90 USD so I thought I would give it a try, much cheaper than the metabones.

To be honest I wasn’t expecting much, but now I have the adapter in my hands I am pleasantly surprised. It appears well made and very solid. It even carries a CE mark. It works just fine on my NEX5N and FS700. On the NEX5N I have working autofocus. If the lens has image stabilisation this works too. I have tried a wide variety of Sigma and Tamron Canon EF lenses with it and they all work. Even my new Tamron 16-300mm works with this adapter, this lens doesn’t work with a number of other adapter.

Autofocus is a little slow, especially if the light is bad. Having not used the MK3 Metabones I don’t know how this compares but certainly this adapter works and is quite useable. It’s said to be compatible with full frame lenses on the A7, but as yet I have not been able to test this. The little mounting post is easily and quickly removable, but a real boon on the NEX5N with bigger lenses. For the price, you can’t go far wrong, really quite impressed considering how little it cost.

What causes CA or Purple and Blue fringes in my videos?

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.

CA1-300x194 What causes CA or Purple and Blue fringes in my videos?
A simple glass lens will bend red, green and blue wavelengths by different amounts, so the focus point will be slightly different for each.

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.

Alphatron ProPull mini follow focus.

IMG_1720-300x225 Alphatron ProPull mini follow focus.
Alphatron MiniPull follow focus.

Over the years I’ve used many different follow focus units. Some better than others, but the majority of them a similar size. I recently got one of the new compact Alphatron Pro-Pull follow focusses to play with. The first and most obvious thing about the Pro-Pull is it’s size. It is very compact. At first I thought this might be an issue as the smaller knob requires more effort to turn than a more conventional larger knob, but in reality it’s not a problem. If you need more torque you can use either a whip or slot in hand grip.

IMG_1724-300x225 Alphatron ProPull mini follow focus.
MiniPull on an F5 working with a Samyang/Rokinon Cine lens.

The Mini-Pull has some really cool features. For a start you can reverse the focus direction by swapping the gear drive from one side of the unit to the other. But the one I really like is the adjustable, locking end stops. This makes it really easy to pull focus from one distance to another. You simply set the stops at your near and far focus positions and then turn the focus wheel between the two stops. If you then need to focus beyond the end stops you simply flip up the latching stop pin and you can focus beyond the end stops. Want to return back to the end stops then simply flip the stop pin back down again. Very clever, very simple and very effective.

The focus marking ring is magnetic so if you need to change or replace this it pulls off easily, yet is very secure when in place. The MiniPull is attached using a simple bracket that attaches to a single 15mm rail. This makes it very easy to adjust the MiniPulls position if your changing lenses and going between different sized lenses. This bracket also makes the MiniPull very compact, which for me as a very frequent traveller is a real bonus.

I used the MiniPull extensively on my recent shoot for the short film “Inviolate” to easily execute a large number of focus pulls. I rate it very highly if you need a compact and easy to use follow focus. It’s supplied with everything you need to get going including a nice flexible lens gear ring and the screw driver needed to attach it. Also included as well as the 0.8 pitch gear drive is a drive wheel with a rubber edge that can be used with lenses without a pitch gear.

HD lenses for 1/2″ Cameras like the EX3, PMW-320 and new PMW-300.

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.