Tag Archives: prime

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!

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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.

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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.

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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.

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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.

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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.

 

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How big a compromise is using a DSLR zoom on a 4K camera?

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.