Using APS-C Lenses on Alpha 7

[Sony Guy]

As a previous NEX 5n & 7 user, I just moved up to a A7 with kit 28-70 full frame lens. I realize how the APS-C lens trade-off thing works on the A7 body (vignetting, etc.) and the A7's menu setting to compensate when using these lenses on it by filling the frame with the cropped image, but at the expense of not being able to utilize the full sensor's capabilities. You're creating an image about one third as big as you'd get with a full frame lens, as a matter of fact.

 

What I'm wondering here is this:

 

How would the image resolutions compare, if I shot a given subject using, say, my SEL18200 (18-200) on the NEX 7, vs. my Alpha 7 (using the "ASP-C Size Capture" function?  Would the images be comparable, or would the A7's sensor boost the image quality up from the NEX 7's smaller pixels?

[Vivek]

There is a very easy way to find out.  Shoot with your APS-C lenses on the FF camera.

[Sony Guy]

There is a very easy way to find out.  Shoot with your APS-C lenses on the FF camera.

Not helpful.

[Michael_j]

Seems a sensible suggestion to me!

 

I can't comment directly as I only have an A7 so can't compare but I do use the 18-200 on it with reasonable results. It is particularly useful for video I find.

 

This is the 18-200 at 135mm equivalent.

 

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The lens covers more than the APS circle so you may find it worth over-riding the auto selection of APS crop 

 

[fotomatix]

As a previous NEX 5n & 7 user, I just moved up to a A7 with kit 28-70 full frame lens. I realize how the APS-C lens trade-off thing works on the A7 body (vignetting, etc.) and the A7's menu setting to compensate when using these lenses on it by filling the frame with the cropped image, but at the expense of not being able to utilize the full sensor's capabilities. You're creating an image about one third as big as you'd get with a full frame lens, as a matter of fact.

 

What I'm wondering here is this:

 

How would the image resolutions compare, if I shot a given subject using, say, my SEL18200 (18-200) on the NEX 7, vs. my Alpha 7 (using the "ASP-C Size Capture" function?  Would the images be comparable, or would the A7's sensor boost the image quality up from the NEX 7's smaller pixels?

Hi I found some useful videos on YouTube that help describe what happens when you use E mount lenses (non FE) on the A7 series. I'm interested in the same information because the FE lense library is limited at the moment in addition to it being very expensive. I know this is to be expected when shooting Full Frame photography however budget is limited at times. I'm currently using the basic kit lens provided, 28-70mm. It's a very good lens, not bad being a 'kit' one. I'm looking for faster and sharper lenses of the f1.4 to f2.8 variety. Until I can afford an Sony or Zeiss FE I was thinking of using a APSC E mount (which I have left over from my NEX 6 days. When you set the A7 to adjust for the lens correction a significant compromise impacts the resolution. If I understand correctly, it is halved. Hence the A7R goes to 16 MP and the A7 to about 12. Still useable for everyday, casual photography or if you want to print no more than 4x6 or 5x7. What do you think?

 

Video 1: 

 

Video 2: 

[fotomatix]

........

The lens covers more than the APS circle so you may find it worth over-riding the auto selection of APS crop 

 

great shot...if I understand correctly you did not enable the camera correction for APSC, however you probably cropped the photo yourself since there is no vignetting visible in your bird photo? Thank you.

[Michael_j]

Not in this case. I normally use the E mount lens at APS setting. I was just pointing out that it will cover more than the APS image circle, especially at the telephoto end of the range,

 

Re fotomatix's post, the image size on APS setting is reduced to about 10Mpx on the A7 but you greatly underestimate the size of print that can be produced. I will quite happily print to A3, in fact some of my bird pics like the one above are printed to A3+ in an exhibition at the moment. It's true that 300 pixels per inch of print is sometimes recommended but it is perfectly possible to produce excellent prints from smaller images. Remember that 10Mpx was a big sensor not so long ago! The point is, I think, that large prints are viewed from a greater distance so the apparent sharpness is the same.

[3irik]

You really should try out your lenses yourself to check how much vignetting you get, and how much you accept. I have used both the Sony SEL 20mm and the Sigma 30mm on my A7, and they both cover a lot more than aps-c, especially if you remove the rear baffle:

 

(put in spoiler because of large images)

 

 

Sigma 30mm @ 2.8 without rear baffle:

 

Sony SEL 20mm @ 2.8:

This one is an older image, and i believe the in-camera picture style was set to "clear" or something, so you might even get more out of it. 

 

 

[fotomatix]

If I understand correctly, when using A7 body APSC crop adjustment, the resolution drops to 10MP from 24MP. I think the quality of the 10MP achieved on a cropped FF is inferior to 10MP achieved on an APSC due to the pixel density per square inch (or square mm). 

In the end, I believe you should ask yourself why do I have a FF camera if I'm going to shoot APSC lenses. Of course I respect 'to each his own' and imagine that those who do this would be doing so for the minority of times (or for selective instances) rather than most of the time. 

[3irik]

But you don't have to use aps-c mode at all. If you use ff-mode you can decide your crop aafterwards, or don't crop at all and get a full frame picture (see the first image in my other post)

[Austerror]

I saw a website somewhere with examples of the 10-18mm E lens on the A7. Worked great between 12mm and 16mm I think it was, after that there was some vignetting.

 

From my point of view, I'd just shoot full frame all the time and crop the results in post.

 

I think the full frame sensor would produce superior results vs the Nex-7. The FF sensor has better everything.  Better higher ISO performance, better dynamic range. The Nex-7 is a few years old now as is its sensor.

[Gilgenberg]

I did some test shot´s with the sigma 19mm APS/C Lens vs Minolta Af 24mm FF Lens.

https://www.flickr.com/photos/97726145@N06/16671654491/in/dateposted-public/lightbox/
I also tried the sigma 30mm EX DN and it works quite well.
I removed the plastic baffle on the sigma Lenses and it comes to useful 17 - 18MP

IQ is a bit better on A7 vs Nex-7 , crisper and a bit sharper, but you have more pixel´s on Nex-7 if you have to crop.

Also the viewfinder has less to show, and you have work in PP (devignetting).
Result: it´s more fun to use FF Lenses on the A7. But in case of the Sigma 19 (and 30mm)
it is so small and light that it is easy to cary it with you, in case you need a Wideangle lens

 

Sony SEL 50F18 and SEL35F18 has less useful MP ( its about 14MP) but OSS works quite well.....but because of less viewfinder image it is less fun to work with it.

[Gilgenberg]

I forgot to say that Sigma 30 DN EX has only some vignetting in the corner...no crop needed.

This lens works very well for FF but you have to remove the plastic lens baffle. (it´s very easy to do!)

 

best regards andreas

[Lefty]

Pixel density is the key, as fotomatix noted. 24mp ff is 2.8mp/cm2, that's about the same as the original A100 at 2.68. By comparison a 24mp APS-C sensor is 6.63, the equivalent of a 50mp+ ff sensor. When you shoot an A7x in APS-C mode you don't change the pixel density, it just chops an APS-C size block out of the middle of it. That said, the A100 was good for A3 prints and was a lot higher density than the A7s at 1.44.

 

I've gotten useable results from APS-C lenses on an A7ii, although I don't do it regularly. In native mode, not APS-C, vignetting varies by lens and generally gets more pronounced the wider the angle. APS-C 16-50mm produces around a 30mm circular image. That makes it full frame vertically, but vignettes substantially at the corners and horizontal sides on ff.

[Golem]

....... .........  I realize how the APS-C lens trade-off thing works on the A7 body

(vignetting, etc.) and the A7's menu setting to compensate when using these

lenses on it by filling the frame with the cropped image, but at the expense of

not being able to utilize the full sensor's capabilities. You're creating an image

about one third as big as you'd get with a full frame lens, as a matter of fact. 

........... .........  

  

--------------------------------------------------------------------------------------------------- 

  

Nope.

  

The image TWO thirds as big. The FF sensor is 36mm wide. The APS-C

image covers a 24mm width on that sensor. 24 is 2/3 of 36. It's linear, not

quadrartic, cuz it's about SIZE [aka magnification], and not about area. 

  

The pixel count [MP's] will fall to 4/9, again not 1/3, but MP's don't matter

when reduction and magnification are measured on the same sensor. It's

simple a case where, as they say, "Size DOES matter" ;-) 

  

 

` 

   

 

[FrankPhillips]

I saw a website somewhere with examples of the 10-18mm E lens on the A7. Worked great between 12mm and 16mm I think it was, after that there was some vignetting.

 

From my point of view, I'd just shoot full frame all the time and crop the results in post.

 

I think the full frame sensor would produce superior results vs the Nex-7. The FF sensor has better everything.  Better higher ISO performance, better dynamic range. The Nex-7 is a few years old now as is its sensor.

 

Hi, folks....this is my first post here.  I did a test of the 10-18mm on my A7 and here are the results so that you can see for yourself:

 

https://flic.kr/s/aHsk9YxzMj

 

Frank

[Lefty]

 

 

 

I think the full frame sensor would produce superior results vs the Nex-7. The FF sensor has better everything.  Better higher ISO performance, better dynamic range. The Nex-7 is a few years old now as is its sensor.

 

 

Yes, but... the Nex-7 has much higher pixel density, and thus the potential for higher resolution. It will out resolve some lenses, which 24mp ff will not do. There's no free lunch. Newer sensors have virtues, but don't discount pixel density too quickly.

[Lefty]

 

Hi, folks....this is my first post here.  I did a test of the 10-18mm on my A7 and here are the results so that you can see for yourself:

 

https://flic.kr/s/aHsk9YxzMj

 

Frank

 

Nice demonstration Frank. Looks like by about 12mm vignetting is gone, and that's wide on ff.

[Yeti]

If one looks carefully, even at 18mm the corners are dark. At 16mm markedly so. (Compare the blue of the sky in the  centre and right hand cornrer, top where it is much darker.) Even other corners lack any detail.

Would be nice if same composition was recorded with a FF lens for real life side by side comparision.

[brian.mccready1]

Hellow sony guy'

I have a sony A6000 and a a7r2, now I have done some testing for myself and printed a picture from the a6000 with my ziess 16-70 apsc lens set at 24mm, and then put the lens on my a7r2 on apsc capture, and set at 24mm, and printed the picture, and to be honest, you would have to be an expert to tell the difference. So one is 24m pixels and the a7r2 is 18m pixels(with no aa filter). the a7 is 10m pixels when on apsc capture, so you would be putting 10m pixels against 24 on the nex camera, so only trial and errer will work on that one. I very often use my ziess 16-70 on my a7r2 as a walk around lens as I am saving up for the ziess16-35. All the full frame lenses are brilliant on the nex. a6000 cameras

[Gilgenberg]

This is with Sigma 30mm 2.8 DN EX and Sony A7S in Full Frame mode

 

somehow the Lens has character so i like it more on A7 than on Nex7 because of that

 

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[kalpachev]

Sony A7RII and modified Sigma AF 60mm f/2.8 DN lens (removed rear baffle):

 

90% of the 42mp frame:

 

London Underground by kalpachev1, on Flickr

 

 

100% of the 42mp frame:

Mind the gap by kalpachev1, on Flickr

[JimmyK]

Hello

 

Here are 2 shots of the same subject, one with the APS-C setting to Off (with the vignette) and one with the setting On. The one with the vignette is 36MP and the one without is 16MP. Zoom in to see the differences; in some situations I would rather switch off the setting and crop the vignette later (being careful with framing the shot with this in mind).

 

Camera = Alpha 7r

Lens = SEL18200

[3irik]

That is at 200mm, right? It looks like you could get a fullframe view if you remove the rear baffle