Sony a6700 camera with Song FE 1.8/50 & Zeiss FE 4/16 lenses

[Lauren]

I was gifted a Sony Alpha 1 camera with 3 lenses- FE 1.8/50 and Zeiss FE 4/16-35 and a telephoto lens that I won't use much since I do mostly portrait photos. I've decided to update the camera (I've already sold it) and am thinking of buying a Sony a6700. My question is would these lenses work with an APS-C camera since they are meant for FF? I mostly do portrait photography, in low light. Up until now I've been using a Nikon D3400 with kit lenses. I'm hoping upgrading to the Song a6700 will help with issues I've had with lighting and autofocus. If the lenses wouldn't work that well with this camera would it be better to buy a FF camera like the Sony a7cii?

[Olaf W.]

6 hours ago, Lauren said:

would these lenses work with an APS-C camera

Yes. But mind the crop factor of 1.5.

[Cameratose]

Why on earth would anyone think an A6700 is an upgrade over an A1? The A1 is Sony's flagship camera. Is this a typo? Was it an A 7? Very confused here. Furthermore, if you are working in low light, spend your dollars on an A7 III. Moving to APS-C is not the best choice for low light, stay with FF. 

To answer your question, yes, they will work, but as posted by Olaf there will be a crop factor of 1.5. 

[Lauren]

1 hour ago, Cameratose said:

Why on earth would anyone think an A6700 is an upgrade over an A1? The A1 is Sony's flagship camera. Is this a typo? Was it an A 7? Very confused here. Furthermore, if you are working in low light, spend your dollars on an A7 III. Moving to APS-C is not the best choice for low light, stay with FF. 

To answer your question, yes, they will work, but as posted by Olaf there will be a crop factor of 1.5. 

Ooops, yes a typo above it was the A7 1 not an A 1

[Cameratose]

39 minutes ago, Lauren said:

Ooops, yes a typo above it was the A7 1 not an A 1

PHEW! I feel SOOO much better! 🤣

I would look at the A7 III, not the A6700. It's an older camera but fully capable, and better low light response. 

[Lauren]

29 minutes ago, Cameratose said:

PHEW! I feel SOOO much better! 🤣

I would look at the A7 III, not the A6700. It's an older camera but fully capable, and better low light response. 

What I like about the a6700 is the AI technology for autofocus that even the A7IV doesn't have. But right now I'm more concerned with the lenses- especially the Zeiss 4/16-35 that I have.

[Cameratose]

Let's be 100% clear:

Sony's AI technology is not true AI. It does not learn. It was programmed using an AI system that learned up to a point, and now that point is locked into the cameras. Moreover, there are complaints about it. For example, it can't tell there's a face inside of an American style football helmet and misses focus.  

The A7 III got the highest percentage in a recent poll for camera models used by pros. If you're shooting mainly portraits as you state, the AI won't come into play much, if at all. Any camera with decent AF can handle that. If you really want to bump up, look at an A7 IV. Watching my A7 IV choose on which eye to focus is amazing. 

[Pieter]

AF on the A7 iv and A6700 should be pretty similar and better than the A7 iii so if AF is high priority, the A6700 is a valid option given that it's €/$ 1000 less expensive than the A7 iv.

[Cameratose]

Each camera's AF is more advanced than the next, in typical Sony fashion. The A7 IV is ahead of the A7 III, and the A6700 is ahead of the A7 IV. However, for portrait work none of that matters. The A7 III's AF is still fantastic, and none of the AI or advanced animal/bird eye focus is going to make a difference in the studio. 

What is important in portraits is a shallow DOF for clean smooth bokeh and good low light response, things that will be more difficult to achieve with an APS-C camera. I would opt for a full-frame camera every time if I were putting my main efforts toward portraiture. In a studio setting, does AF even matter? For the same $, the A7 III would be my choice between the two, hands down. With a bit more to spend the A7 IV, or for that matter the A7c or A7cII if that form factor is desired.  

[Pieter]

I guess for OP's specific use case you have a good point: A7 iii and A6700 cost about the same where I live. But bear in mind there's a limit to the shallowness of DoF one can have for nice portraiture (and thus, a limit to the benefit of fullframe over APS-C). Do you really want only the eyes in focus and the nose/ears blurred? E.g: If - for DoF-considerations - you want to shoot 85mm f/2 on Fullframe, might as well shoot 56mm f/1.4 on APS-C with nearly identical low light performance.

However, given the fact that OP already has a selection of fullframe lenses, I'd want to keep the option open to take benefit from that larger sensor, and thus buy a FF camera.

[Cameratose]

"Do you really want only the eyes in focus and the nose/ears blurred?"

No of course not. But it'd be much easier to achieve good background bokeh with the FF sensor. 

The low-light performance would not be identical. I'll grant that the setting you propose would provide similar results, but you also have to take the starting point into account. The A7 III has better DR to begin with, 2/3 of a stop at base ISO. (Photons to Photos) The A7 III's sensor is one of the best in low light, when it comes to higher ISOs (DXOMark). It's unfortunate they never ranked the A6700, not sure why.  

In any event, either camera would do the job, but I think the FF would be a better choice for the reasons mentioned.  

 

[Pieter]

22 minutes ago, Cameratose said:

The A7 III has better DR to begin with, 2/3 of a stop at base ISO.

This is a rather hypothetical discussion but in my example and at anything over base ISO, the DR advantage of the A7iii is compensated for by a stop lower ISO on the A6700, assuming shutter speed and DoF are constant. But yes, the A7iii excels at higher ISOs where the DR advantage of the A7iii is like 4/3 of a stop over the A6700, giving it a marginal benefit over the A6700.

My point is: Ff really shines at (equivalent) aperture settings unavailable to APS-C, but these settings are not always relevant. E.g. in the case where you don't want paper thin DoF.

Edited January 6 by Pieter