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APSC Lenses on A7Rii (Aperature Equivalence)

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AdrianGail View Drop Down
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Post Options Post Options   Quote AdrianGail Quote  Post ReplyReply Direct Link To This Post Topic: APSC Lenses on A7Rii (Aperature Equivalence)
    Posted: 05 January 2018 at 11:36
Hi,

So I'm letting go of my trusty old A77 and moving on. I've been having a big debate with myself whether to move to stay with A-mount (A99ii) or jump ship to E-Mount (A7Rii) - But that's probably for another topic.

I'm planning on adapting a couple of my FF A-Mount lenses (LA-EA3) onto the A7Rii and I had a question... What happens in the following case where I adapt an APSC lens:

A7Rii + LA-EA3 + Sony DT 16-50mm F2.8 SSM

I'm happy that the camera goes into crop mode (~18MP) and the "equivalent" focal length of the lens will yield 24-75mm, but what happens to the aperature? My understanding suggeststhat you also get an equivalent aperature f/2.8=~f4 - Or because aperature is a physical characteristic of the lens focal length f/2.8 does it remain the same? (thinking not)

I'm just thinking, When looking at the end result image; background seperation, etc, will the crop mode' 16-50f2.8(APSC) be 'equivalent' to the FE24-70f2.8 or more like the FE24-70f4

Essentially - am I getting an 18MP 24-75f2.8 or 18MP 24-75f4 image out the camera.


Sorry for the brain dump... I'm not a working photographer by any means so I'm trying to maximise what I can get with my hard earned pennies. I was planning on buying an FE lens with the camera, my ideal would be the 24-70f2.8GM but obv that is still about £1700 after cashback, I would opt for the 24-70f4 Zeiss, but if I'm getting an 'equivalent image'* I wouldn't buy that right now, but hold off and save for the GM or buy an FE prime...

Thanks in advance for a) the technical info and b) putting up with my ramblings.


*ignoring all aspects of the actual IQ dif because of the lens/glass and the benefit of all the native features that I might miss out on
 



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C_N_RED_AGAIN View Drop Down
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Post Options Post Options   Quote C_N_RED_AGAIN Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2018 at 11:38
Your images will look like the 18 mp 24-70 f4
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C_N_RED_AGAIN View Drop Down
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Post Options Post Options   Quote C_N_RED_AGAIN Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2018 at 11:40
Btw the 24-105 f4.is just as sharp as the gm. Cracking lens. And the bokeh is very good especially obviously at it's longer end
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QuietOC View Drop Down
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2018 at 14:55
Originally posted by C_N_RED_AGAIN C_N_RED_AGAIN wrote:

Your images will look like the 18 mp 24-70 f4

Yes, the effects of aperture on image quality scale with cropping--any cropping, not just using a special APS-C mode. Exposure still only works with the F2.8 number, but exposure by itself doesn't determine image quality.

Where you really want to use APS-C lenses on the A7RII is for video capture because the Super 35 video capture modes have better image quality than the full-frame video capture modes.
A68 30M 35 50 60M 16-50 16-80 18-55 18-70 18-135 55-200 55-300
A6000 LA-EA1 6.5 16 20 30 50 60 16-50 18-55 55-210
600si: 20 24 28 50 100M 135 24-85 24-105 28-105 35-70 35-105 70-210 75-300 100-200
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maewpa View Drop Down
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Post Options Post Options   Quote maewpa Quote  Post ReplyReply Direct Link To This Post Posted: 06 January 2018 at 05:16
While it's not wholly on topic, I don't think you should see the investment in full frame lenses as separate from the investment in the camera. Moreover, adapted lenses (especially Sony SSM II) will work quite well but not as well as native lenses if you are doing walkabout/travel shooting. This is especially true with the A7Rii (now we have the A7Riii to compare it to). You really have to be aware of each lens' limitations or you will miss shots. If you do switch to e-mount (and I recommend it if you are seriously into something that the e-mount cameras do well or want the lightweight/small option) at least try to get a 28/2 to play with while you save up for a 24-70 or 24-105 (which you definitely need to add to your list).

If you can wait, then I would suggest you do and see if an A7iii is coming as it might actually be a better choice for 80% of needs, especially compared to an older model like the A7Rii. If it isn't what you want, at the very least it will likely knock down the price of the A7Rii further and you can get the 24-105 at the same time.Having used the A7Riii for a few weeks now, I would be loathe to recommend buying an A7Rii unless you are sure it is the tool you are looking for. It's a great camera but it's amazing what a little more technology and design can do.

But that's the separate question..... and I haven't used an A99ii.
Paul aka maewpa
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Post Options Post Options   Quote DrFZs Quote  Post ReplyReply Direct Link To This Post Posted: 06 January 2018 at 08:26
Hi!

I have 99II.
If I use it in APS-C mode with high ISO the pictures will be worse then with FF.
I dont recomend using APS-c lens with FF body.

If your budget is enough the best body the 99II.

Cheers:
DrFZs
 



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addy landzaat View Drop Down
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Post Options Post Options   Quote addy landzaat Quote  Post ReplyReply Direct Link To This Post Posted: 06 January 2018 at 09:44
First, why do you want to go to full frame? What full frame lenses do you have?

Second, your APS-C lenses will behave the same as they do on your APS-C A77. NO change. Full frame lenses make a difference though.

The way the "aperture equivalence" discussion is conducted is confusing and it is done in a very technical way and the people who do it never ever show pictures it seems. The "problem" is not that you are not a "working photographer" but that you're not an engineer

If you take a picture with a full frame camera with a full frame lens and crop the picture to APS-C size, you get the APS-C picture. The DoF is the same, the field of view is just smaller making it feel like a longer focallength. That means the 16-50/2.8 on APS-C feels like a 24-75/4 on full frame.

It you're worried about your hard earned pennies, buy the A77m2 - the AF is a huge leap ahead and even the sensor is better then your A77.
Why not follow me on Instagram? @Addy_101
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sybersitizen View Drop Down
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 06 January 2018 at 10:17
Here's another way to look at things:

Let's say you take a nice photo with the A77 and a 16-50mm DT lens at f/2.8 and ISO 100. The resolution would be 24MP.

You could take a nearly identical photo with the A7RII and LA-EA3 and the same 16-50mm DT lens at f/2.8 and ISO 100; but the resolution would then be about 18MP.

You could also take a nearly identical photo with the A7RII and a 24-75mm full frame lens at f/4 and ISO 200; but the resolution would be 42MP.

You would be using the same shutter speed in all cases.

However, we should also consider the facts that 1) the A77 has an SLT mirror, and 2) the A7RII has a newer, more advanced sensor and signal chain that performs better. When those things are taken into consideration as well, you can expect both of the A7RII results to actually look cleaner than the so-called 'equivalent' result of the A77, particularly in low light situations.

Edited by sybersitizen - 06 January 2018 at 10:27
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jkp1 View Drop Down
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Post Options Post Options   Quote jkp1 Quote  Post ReplyReply Direct Link To This Post Posted: 06 January 2018 at 11:15
Originally posted by QuietOC QuietOC wrote:



Where you really want to use APS-C lenses on the A7RII is for video capture because the Super 35 video capture modes have better image quality than the full-frame video capture modes.


....hmmm...seems not to be the case when speaking about A7R3....?
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QuietOC View Drop Down
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Posted: 06 January 2018 at 11:34
Originally posted by jkp1 jkp1 wrote:

Originally posted by QuietOC QuietOC wrote:



Where you really want to use APS-C lenses on the A7RII is for video capture because the Super 35 video capture modes have better image quality than the full-frame video capture modes.


....hmmm...seems not to be the case when speaking about A7R3....?

From the reviews they've improved the full-frame video capture on the A7RIII, but the Super35 is still better. And the A6300/A6500 video capture is better than the Super35 modes of the A7RII and A7RIII.
A68 30M 35 50 60M 16-50 16-80 18-55 18-70 18-135 55-200 55-300
A6000 LA-EA1 6.5 16 20 30 50 60 16-50 18-55 55-210
600si: 20 24 28 50 100M 135 24-85 24-105 28-105 35-70 35-105 70-210 75-300 100-200
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Post Options Post Options   Quote jkp1 Quote  Post ReplyReply Direct Link To This Post Posted: 08 January 2018 at 20:50
I have to disagree.
Cant see any areas where s35 have advantages over the full frame, and i can only see the A6500 excel when speaking about stabilization, nothing else.
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AdrianGail View Drop Down
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Post Options Post Options   Quote AdrianGail Quote  Post ReplyReply Direct Link To This Post Posted: 09 January 2018 at 11:40
Originally posted by maewpa maewpa wrote:

If you do switch to e-mount (and I recommend it if you are seriously into something that the e-mount cameras do well or want the lightweight/small option) at least try to get a 28/2 to play with while you save up for a 24-70 or 24-105 (which you definitely need to add to your list).


Without starting another debate I'm also a bit worried they can A-mount at some point. Although I'll probably have the camera body for another 3/4 years it probably won't be too much of an issue.

There's also the worry that the fast Hybrid AF doesn't 'apparently' work on the A99ii with all A-mount AF lenses and I can't really find a definitive list other than the obvious sony website which basically lists the newer SSM lenses. (I'm wondering about 3rd party / older Minolta lenses etc)

I'm not especially into the smaller form factor of e-mount... in fact, I've also budgeted for a vertical grip, but then I've also always had the VG-C77AM on my A77 (which I contemplated taking over to the A99ii when I was considering that)


Originally posted by maewpa maewpa wrote:


If you can wait, then I would suggest you do and see if an A7iii is coming as it might actually be a better choice for 80% of needs, especially compared to an older model like the A7Rii. If it isn't what you want, at the very least it will likely knock down the price of the A7Rii further and you can get the 24-105 at the same time.Having used the A7Riii for a few weeks now, I would be loathe to recommend buying an A7Rii unless you are sure it is the tool you are looking for. It's a great camera but it's amazing what a little more technology and design can do.

But that's the separate question..... and I haven't used an A99ii.


It's the old... do I wait... do I take the plunge. Which I'm terrible at. It's funny because the A7Rii was mind-blowing for all when it was released, but tech moves on and a year or so later people would dream of owning it over the A7Riii - I'm maybe a bit old-school where I think, if it worked so well when it was released it should still be a great camera when not compared with a newer model?


Originally posted by addy landzaat addy landzaat wrote:

First, why do you want to go to full frame? What full frame lenses do you have?


I think it's a natural progression - I've been taking photographs for the last 15-16 years (it may not seem long but I'm a spritely 34 years of age :D ) and started on a Canon compact, then early G-series, then a bridge, the a100, a200, a77... I thought of the A77ii but it's getting on a bit. which goes back to my worry about A-mount development.

Originally posted by addy landzaat addy landzaat wrote:


Second, your APS-C lenses will behave the same as they do on your APS-C A77. NO change. Full frame lenses make a difference though.

The way the "aperture equivalence" discussion is conducted is confusing and it is done in a very technical way and the people who do it never ever show pictures it seems. The "problem" is not that you are not a "working photographer" but that you're not an engineer


That's funny :lol: I'm an engineer (now manufacturing programme manager) with an engineering degree working for a defence electronics company manufacturing fire control radar for fast jets... suppose it doesn't make me a good engineer :D I understand the principle, but sometimes you read things online and they can make you question yourself.

Originally posted by addy landzaat addy landzaat wrote:


It you're worried about your hard earned pennies, buy the A77m2 - the AF is a huge leap ahead and even the sensor is better then your A77.


Yeah... I've ruled that out. I'm just being frugal and I'm willing to spend money, just not all at once.

Edited by AdrianGail - 09 January 2018 at 11:53
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maewpa View Drop Down
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Post Options Post Options   Quote maewpa Quote  Post ReplyReply Direct Link To This Post Posted: 11 January 2018 at 05:53
Originally posted by AdrianGail AdrianGail wrote:

Originally posted by maewpa maewpa wrote:

If you do switch to e-mount (and I recommend it if you are seriously into something that the e-mount cameras do well or want the lightweight/small option) at least try to get a 28/2 to play with while you save up for a 24-70 or 24-105 (which you definitely need to add to your list).


Without starting another debate I'm also a bit worried they can A-mount at some point. Although I'll probably have the camera body for another 3/4 years it probably won't be too much of an issue.

There's also the worry that the fast Hybrid AF doesn't 'apparently' work on the A99ii with all A-mount AF lenses and I can't really find a definitive list other than the obvious sony website which basically lists the newer SSM lenses. (I'm wondering about 3rd party / older Minolta lenses etc)

I'm not especially into the smaller form factor of e-mount... in fact, I've also budgeted for a vertical grip, but then I've also always had the VG-C77AM on my A77 (which I contemplated taking over to the A99ii when I was considering that)


Originally posted by maewpa maewpa wrote:


If you can wait, then I would suggest you do and see if an A7iii is coming as it might actually be a better choice for 80% of needs, especially compared to an older model like the A7Rii. If it isn't what you want, at the very least it will likely knock down the price of the A7Rii further and you can get the 24-105 at the same time.Having used the A7Riii for a few weeks now, I would be loathe to recommend buying an A7Rii unless you are sure it is the tool you are looking for. It's a great camera but it's amazing what a little more technology and design can do.

But that's the separate question..... and I haven't used an A99ii.


It's the old... do I wait... do I take the plunge. Which I'm terrible at. It's funny because the A7Rii was mind-blowing for all when it was released, but tech moves on and a year or so later people would dream of owning it over the A7Riii - I'm maybe a bit old-school where I think, if it worked so well when it was released it should still be a great camera when not compared with a newer model?


Re waiting, I guess it is possible there might not even be an A7iii (although that would be strange) or that an A7siii will end up a higher priority. But waiting would definitely have been wise 12 months ago - the choices from everywhere now seem significantly better.. probably a reason why now waiting will be less fruitful (except for that A7iii maybe ).

Re. the other stuff, I was actually making an assumption based on your apparent (also assumed) 16-50 love i.e. you are like me and value utility. Since at least the A9 (maybe since a 6xxx camera - I am not sure as I don't use that series) e-mount cameras have notably improved in that respect - you could even say that is the only point of the Riii over Rii - improved utility. If my assumption is wrong ignore my apparently unflattering comment about the Rii. I wouldn't hesitate to recommend it based on e.g. quality, as a hybrid stills/video tool, etc.

And yeah, A mount makes sense but yes again, you're probably going to switch at some point in the future. However (further off topic) e-mount barely has more in common with a-mount than any other brand does. As things now stand many Canon lenses actually work better than many Sony lenses via adaptor... a sobering fact. Adaptor technology drives compatibility faster than camera technology. Most A-mount lenses will work better on an A99ii but you'll have a hard time getting information about compatibility of asp-c lenses. Interest in such info would be very limited.
Paul aka maewpa
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