But here are some 24mm Sony shots. I did not shoot a lot with this lens as I was more concentrating on my CV glass that I would normally take into the field. The Sony for me is more a work lens
IzelPhotograph wrote:
But you're also only trying to cover half the area.
If at FF you're 1.4 exposure @1.4 is 1/125, ISO100 then changing to crop mode your exposure [email protected] is 1/125, ISO100. Effectively (in crop mode), you're not reducing the amount of light, your reducing the amount of space the light can fall onto. It doesn't alter the speed of the lens.
If you print a picture and then trim a couple of inches off the side of it, the image that remains still has the same intensity as it did before you trimmed it.... it doesn't fade because less ink is visible.
Now, this will alter the depth of field but it has zero impact on the exposure. ...Show more →
The number of photons captured will be different, don't you think this affects the image?
When photon noise limited S/N scales with sqrt(S) and will be higher with FF.
DOF changes, too.
Of course there is a trade off in image quality, that has been acknowledged, you’re throwing away 24Mp of data by using crop mode. Would a 35mm on FF yield better results than a 24mm in crop mode, sure your capturing far more data and can use the full ability of the sensor.
Using a lens in crop mode though, still doesn’t change its effective aperture, only how much of the image is recorded. Image magnification of the final output will be limited by the captured size and Mp of the recorded cropped image, just as if the image had been cropped in post.
Steve Spencer wrote:
Although it is true that in crop mode (or on a camera with a smaller sensor) the ISO, shutter speed, and aperture will remain the same as when you shoot the same lens on FF, there will be an important difference in practice when you are shooting in some circumstances. If you have limited light, you will notice noise faster when you shoot in crop mode because you are in effect magnifying the image which includes magnifying the noise. In practice this means that if you could shoot ISO 3200 and not be bothered by the noise when shooting FF, when shooting in crop mode you will only be able to shoot at ISO 1600 and not be bothered by the noise. At the opposite extreme when you have lots of light (perhaps too much to capture it all) and you would be shooting with ISO 100 to maximize dynamic range and you just have enough dynamic range to no blow the highlights using 3 stops of shadow recovery to get the right detail out of the darkest part of the image, if you shoot in crop mode if +3 stops was the max shadow recovery that retained a good image, you will only be able to go to +2 stops of shadow recovery. Again because you are magnifying the image you are magnifying the noise in the shadows and you won't be able to push them as far. You will see these same issues whether you shoot a FF image and crop or whether you use a camera with a smaller sensor....Show more →
When using the crop mode function (1.5x) on a full frame camera, the consequences will be:
(BTW: The same for cropping in post or using an equiv. crop camera)
1) Resolution change: In the case of the A7R III sensor, there will be a resolution drop from 42MP to ~18.7MP. (42/1.5/1.5)
2) Field of view change: (24x1.5 = 36mm full frame equiv.)
3) Depth of field change: So a f/1.4 lens becomes full frame equivalent to a f/2 lens in terms of depth of field.
4) Dynamic range loss from a noisier image: If you use the crop mode with the 24/1.4 GM, it will be like shooting with a ~35/2 equiv. but the image dimensions will be smaller. When that’s compared to a full frame image taken with a real 35/2 lens, if we equalize image dimensions by resizing the full frame image to match the crop, the later will have about 1 stop less noise (higher DR) compared to the latter.
So, when using the crop mode on the 24/1.4 GM lens, depth of field will be equivalent to f/2 in full frame terms and noise levels will about 1 stop higher. (square of 1.5 = 2.25x)
This is tricky…even though it seems the 24/1.4 cropped to 35mm is still gathering the same light when looking at the camera settings, when we equalize image size by resizing the full frame image to match the cropped image dimensions, the crop file will show more noise and therefore lower dynamic range.
Moral of the story: I agree that it seems counterproductive to use your full frame 24/1.4 GM lens in crop mode or on a crop camera BUT depending on the subject, it could be a bonus as long as we know we are not getting the full benefit of shooting with a full frame sensor.
Example and some math:
Shooting with A7RIII + 24/1.4 GM wide open at ISO 400 (42MP) in "APS-C crop mode" will yield an image equivalent to ~35/2 ISO 900 (18.7MP) when both images are equalized.
42/1.5/1.5 = 18.66 MP
24 x 1.5 = 36mm
f/1.4 x 1.5 = f/2.1
ISO 400 x (1.5 square) = 400 x 2.25 = ISO 900
Holger wrote:
The number of photons captured will be different, don't you think this affects the image?
When photon noise limited S/N scales with sqrt(S) and will be higher with FF.
DOF changes, too.
Yeah, I did mention the DoF, which is the main (only, mostly) visible difference.
As far as photons are concerned. If I take a shot from a tripod in FF and in crop mode (same exposure settings) then view them at 100% and can't tell the difference in terms of IQ..... then no, I'm not concerned.
I know for certain if I can't spot it then neither will the clients. There are enough things to think about that do influence the outcome of an image that spending time on the things that aren't visible to the human eye seems a little silly. This would be a case of science getting in the way of photography rather than helping it.
Personally, I rarely use crop mode (other than footage) as I like to have the option to crop afterwards if it's needed. But, I do have the crop mode set to the centre button so I can quickly toggle between FF and Crop mode to check out at a possible composition with fine tuning carried out later in C1.
Thank you Fred for the exposition. Very helpful and informative.
I think the wording in your final example may be a tiny bit confusing to some (count me in!). If I understand what you are saying, if you START with an A7R3 and the 24mm 1.4 GM @ f1.4 at ISO 400 and you push the crop button, you will END UP with an image equivalent to 36mm f2.1 ISO 1000. The actual images themselves will not be "similar". Right?
Fred Miranda wrote:
When using the crop mode function (1.5x) on a full frame camera, the consequences will be:
(BTW: The same for cropping in post or using an equiv. crop camera)
1) Resolution change: In the case of the A7R IIII sensor, there will be a resolution drop from 42MP to ~18.7MP. (42/1.5/1.5)
2) Field of view change: (24x1.5 = 36mm full frame equiv.)
3) Depth of field change: So a f/1.4 lens becomes full frame equivalent to a f/2 lens in terms of depth of field.
4) Dynamic range loss from a noisier image: If you use the crop mode with the 24/1.4 GM, it will be like shooting with a 35/2 equiv. but the image dimensions will be smaller. When that’s compared to a full frame image taken with a real 35/2 lens, if we equalize image dimensions by resizing the full frame image to match the crop, the later will have about 1 stop less noise (higher DR) compared to the latter.
So, when using the crop mode on the 24/1.4 GM lens, depth of field will be equivalent to f/2 in full frame terms and noise levels will about 1 stop higher. (square of 1.5 = 2.5)
This is tricky…even though it seems the 24/1.4 cropped to 35mm is still gathering the same light when looking at the camera settings, when we equalize image size by resizing the full frame image to match the cropped image dimensions, the crop file will show more noise and therefore lower dynamic range.
Moral of the story: I agree that it seems counterproductive to use your full frame 24/1.4 GM lens in crop mode or on a crop camera BUT depending on the subject, it could be a bonus as long as we know you are not getting the full benefit of shooting with a full frame sensor.
Example:
Shooting with the 24/1.4 GM wide open at ISO 400 (42MP) will yield a similar image to shooting @35/2 ISO 1000 (18.6MP) in crop mode....
42/1.5/1.5 = 18.66 MP
f/1.4 x 1.5 = f/2.1
ISO 400 x (1.5 square) = 400 x 2.5 = 1000 ...Show more →
Yes, the keyword here is to view the FF and cropped pictures at the same size. I think most people find it confusing when they simply zoom to 100% on both pictures and couldn't find anything difference. The equivalence talk is hard to visualize when people don't normalize the results.
For most shooting, I am boggled that anyone would use crop mode - just use shoot normal and crop after the fact and you can have control over your crop!
HOWEVER
After struggling with storage/backup/filesize anxiety ever since moving the the "R"'s (A7R, A7RII, and now A7RIII), I love having a lower file size for pics that will never be printed - I'm talking about all my family moments of mealtimes, hikes, funny faces, etc. that are meant for capturing quick memories, etc. to send to grandparents, etc. I'm perfectly happy using crop mode (esp. now that I can still use RAW in the RIII) and don't care at all if they are slightly higher noise, etc.
While I don't see much reason to use it in "serious" photography (in my use cases), I still see it as an immensely useful feature.
Cropping in post is not always a option when your shooting 20k images in a couple days. Im not that crazy to do that to myself. Im forced to shoot crop mode because Sony forgot to make ME A FREAKING 300mm 2.8
Yes its supposed to be a GM with my initials on it. WTF
Seriously this would not even be a discussion if Sony made a 35mm 1.8 lens. But it is a option we can use
It's helpful and convenient to have the mode available as others have stated. I like being able to have smaller file sizes if the larger ones are not necessary for the given scenario and I only have my one rig.
More importantly regarding just shooting in ff mode and cropping in post, there are still many of us that would prefer to get it mostly right in cam at the time of capture. Being able to see the actual framing for the FL you're wanting to shoot at is an integral part of this.
With regard to viewing quality, post remodel of our house last month, the ole lady asked me to get a bunch of 16x20 metal prints.
In a scramble, I chose some of our favorites from over the last 5-7 years. Many of those were out of APSC cameras that only had 16mp (some even further compressed and/or cropped a bit) e.g. X-T1 and X-100s. They still look legit barring me having my face within 6 inches of them. The end.
IzelPhotograph wrote:
Yeah, I did mention the DoF, which is the main (only, mostly) visible difference.
As far as photons are concerned. If I take a shot from a tripod in FF and in crop mode (same exposure settings) then view them at 100% and can't tell the difference in terms of IQ..... then no, I'm not concerned.
I know for certain if I can't spot it then neither will the clients. There are enough things to think about that do influence the outcome of an image that spending time on the things that aren't visible to the human eye seems a little silly. This would be a case of science getting in the way of photography rather than helping it.
Personally, I rarely use crop mode (other than footage) as I like to have the option to crop afterwards if it's needed. But, I do have the crop mode set to the centre button so I can quickly toggle between FF and Crop mode to check out at a possible composition with fine tuning carried out later in C1....Show more →
I usually can make use of the stop difference at weddings (e.g. using 24 or 35mm at f1.4 and still get enough DOF; on the dance floor to keep ISO down and allow larger prints). For many use cases the stop difference isn't that dramatic and I wouldn't worry.
Holger wrote:
I usually can make use of the stop difference at weddings (e.g. using 24 or 35mm at f1.4 and still get enough DOF; on the dance floor to keep ISO down and allow larger prints). For many use cases the stop difference isn't that dramatic and I wouldn't worry.
When dealing with scenarios like that where light is at a premium, f/1.4 lenses come into their own. Freezing any action and keeping ISO's down to an acceptable level is key. Sometimes I'll just dial in ISO 640 set the speed to what is needed then lift exposure in post. That said, when ever possible I prefer to other expose by 1-2 stops and bring it back down in post.
Back to the 24 f/1.4
It arrived today and the first thing I thought was, bloody hell, that's small! Build quality seems excellent and initial shots (although only a few) are impressive. Hopefully will get out tomorrow to try both it and the Batis 40 out properly.
Another one to comment on small size. Many have been asking for small FE lenses, so looks like Sony figured out to make a small AF, high quality FE lens. More fuel to my GAS fire!
GMPhotography wrote:
I never noticed the one stop, I’ll double check today
I do occasionally. In Germany some churches are quite old (had a wedding not long ago here, for example (built around 1150): https://de.wikipedia.org/wiki/St._Peter_zu_Syburg). No flash allowed, usually. You are quickly at iso6400-iso12800. Being able to half the iso with f1.4 fs. f2 or have 2.25 times larger sensor area compared to APSC comes in handy.
Shooting at 24/1.4 vs. f2 is something to my liking, too. I notice that.
Okay update i bought the Haoge 67mm rectangle hood and it works without vignetting and you can actually grab the hood and take lens off body or at least use most of it
Holger wrote:
I do occasionally. In Germany some churches are quite old (had a wedding not long ago here, for example (built around 1150): https://de.wikipedia.org/wiki/St._Peter_zu_Syburg). No flash allowed, usually. You are quickly at iso6400-iso12800. Being able to half the iso with f1.4 fs. f2 or have 2.25 times larger sensor area compared to APSC comes in handy.
Shooting at 24/1.4 vs. f2 is something to my liking, too. I notice that.
Im not seeing a full stop. Maybe 1/3 or so but seems to vary as well. Im playing with it now
GMPhotography wrote:
Okay update i bought the Haoge 67mm rectangle hood and it works without vignetting and you can actually grab the hood and take lens off body or at least use most of it
