October 19, 2015 at 9:23AM


What do you think of this lenses set for 4K?


I'm going to acquire some equipment to primarily shot music videos and the like-therefore I'll work in a controlled environment- and I would like some opinion on these lenses. They will meet an a7s so keep the dual focal length in mind, due to aps-c mode. I thought of a Canon 24-70 f4 as a solo lens, but then I knew that the Tamron 24-70 f2.8 would be better for that price. However I'm thinking of spending a little more and buy the following ones in order to have a wider choice and faster and sharper lenses:

-Samyang 14mm 2.8 (also a 21mm)
-Sigma 18-35mm 1.8 (only aps-c, so it's a 27-56mm actually)
-Samyang 85mm 1.4 (also a 130mm)

As far as I know, the a7s only records 4K in Full frame mode, so I'll need to keep the great Sigma out of the team for the sake of the greater resolution. Two questions:

i) What do you think of this set? Would you change something for that price? There's always this lens I'm not aware of and it's THE bang for the buck, so any help will be appreciated.

ii) If I just wanted to go the one-lense way, what would you replace the Tamron with?

Thank you sooo much! As you would've noticed, I'm not a native speaker so excuse my grammar ; )


A7s does not record 4k natively. It records 4k externally.

The crop mode has a visually impaired quality as far as I can tell. I never shoot crop for that reason as on my A7s the noise spikes up.

With regards to focal lens -- this is a question that you need to answer yourself. You need to know what length you like. For example over the time I discovered I used only two lenses: a 35mm and a 135mm. Everything else just takes extra time and effort to think off.

October 21, 2015 at 9:19PM

Alex Zakrividoroga

Ignore what Alex says about Crop Mode. Yes, it does raise the noise floor, but I found I could still shoot up to ISO 12,800 with useable results. One stop less than FF mode (which I only found to be useable up to 25,600). When I had that camera, I shot almost everything in crop mode, since it dramatically reduced the rolling shutter.

I would personally stay away from Canon's zooms. I don't consider any of them to be worth the price for video. The Tamron is definitely better value, and it might work as a stand-alone lens, but it also has a backward focus ring--not a big deal if it's your only lens, but as your collection expands, you will find yourself hating it (or hating all your newer lenses!).

My personal recommendation is a Contax Zeiss 35-70mm f3.4 for $300-400. I used it for a little while on the A7s, and it's awesome. It gives you a nice wide in FF mode, but you can get in pretty tight in APS-C mode as well. And the coatings on that lens are beautiful! Plus, at the 35mm end, you can use it in macro mode. It really has everything you could need. Yes, it is a little slow (only f3.4), but you can always boost the ISO on your camera a bit to compensate.

The only thing you'll be missing out on is a wide aperture for those really shallow depth of field shots. f3.4 gets you there most of the time, but sometimes you just need it to be shallower. That's why I recommend getting a Contax Zeiss 50mm 1.4 for $300. Incredible all-around lens.

Those lenses are Contax/Yashica mount; you can get a C/Y to E-mount metabones adapter for $100 (don't go for a cheap brand!). So, for about $800, you're getting a great zoom and a great prime, with the nice Zeiss coatings, that covers you from 35mm in full frame to the equivalent of 105mm in crop frame (70mm x 1.6).

Really, I can't recommend Contax Zeiss lenses enough.

October 22, 2015 at 9:40PM

Kenneth Merrill

Thanks Kenneth. Good info.

Jeff Worden

October 23, 2015 at 12:46PM

Great response, Kenneth. I'll definitely check that lenses out. Thanks!


October 26, 2015 at 3:34PM

I have a set of Contax primes that I use on the Red. Beautiful lenses and a great investment! I'll consider getting this zoom lens.

Sathya Vijayendran

October 28, 2015 at 3:01PM

I would recommend going with all samyangs, just getting a 24mm, a 35mm and a 50mm instead of a sigma. You're not going to lose all that much given the small zoom range of the sigma

October 23, 2015 at 5:14PM


Sorry, but I have to disagree again. The Samyangs are terrible. I meant to say that earlier, but I forgot. Please don't get Samyangs. The contrast is terrible, which is why they always look so soft. And the build quality is equally as bad.

Just don't.

October 23, 2015 at 5:43PM, Edited October 23, 5:43PM

Kenneth Merrill

For their price, the Samyang/Rokinon's are great. They're sharp and I'm actually quite impressed with the build quality. Obviously they're not as good as, say, the Zeiss CP2's, but much more affordable.

Basing this on the fact that I own the 35mm T1.5.

Paul Cummings

October 24, 2015 at 2:58AM

unless you are in constant changing lighting conditions, i can live with non-declicked apertures. I'd rather get some used zeiss zf's or contax lenses and adapt them. The image will be better.
and also the title of the topic is incorrect. you chose lenses for the crop factor. not the size of the output.

October 24, 2015 at 6:55AM

Kazu Okuda

Preferably lenses out-resolve the resolution of the sensor (so that the camera is the resolution bottleneck, not the glass). Thus 4K vs. HD does theoretically matter when shopping for lenses, but most modern or modern-ish lenses are easily 4K capable (4K = around 9 MP). Then again, perceived sharpness and the final resolving power of an imaging system isn't quite that simple a formula, especially for moving images. So you will still notice the increased sharpness afforded by more impressive glass vs inferior stuff, even in HD.

Einar Bjarni Davidsson

October 25, 2015 at 3:25PM

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