Q3 Crop Modes and Equivalent Depths of Field Question

[nariza7]

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So quick situational question then. If you took a photo of someone at 28mm f1.7, but framed it so there’s room to crop a little. Then you crop it so it’s like 35mm equivalent. How would the depth of field perception be answered? Won’t it still look like the original 28mm f1.7 (rendering wise), but with edges taken off? What would be the perceived depth of field?

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[jaapv]

The DOF would be a bit less shallow, maybe something like 2.0  For wideangle work it makes no significant difference at all. For the rest it would look  exactly like any 35 mm lens shot. 

[adrianh]

As this has been discussed in many many threads previously I would suggest a more practical and pragmatical approach. If you have another camera at hand, take pictures with whatever lens you have on the other camera and try to do something similar with a Q3 in an equivalent crop factor. I think a 50mm 1.8 against 1.7 50mm crop mode would be enough that you experience the differences. 

But if the Q3 is your only camera than I suggest you take a picture of something near (or a portrait) at 1.7 with the 75 or 90mm crop mode and see if for you, the DoF you can see is shallow enough for your liking. Theoretically, it shouldn't be, as the 90mm crop DoF will be very far away from a real 1.7 90mm or even 75mm lens but hey, if you like it and it is enough for you, so be it! You should be happy with the results independently of all that grey theory 😃

Edited November 4, 2023 by adrianh

[mca]

I just came accross this topic and it has been an interesting read. But I find a lot of misconceptions which I thought in this technically savvy community would be rare.  

I am not a very technical oriented guy but I know from experience that cropping an image taken with a wider focal length (like a 28mm) to look like a narrower focal length (like a 50mm or a 90mm) is very different from shooting with the narrower focal length lens in the first place, namely in terms of depth of field which is the topic of discussion here.

 

For those who think it's the same to shoot wide and crop vs shoot narrow to begin with, if you have any 2 different lenses on your camera, I suggest you test it yourself at home, it's fairly easy:

- put the camera on a tripod and take a picture with the wider of the 2 lenses at a fairly open aperture like f/2 or f/2.8;

- then switch to the longer lens and repeat the process using the same f/2 or f/2.8 aperture used in the first photo;

- then go to the computer and open the 2 images side by side, and crop the first image to look like the second image (so that both have the same field of view);

- now compare the out of focus areas in both photos and you should see a clear difference!

 

When you shoot with a 28mm at f/2 for example, and then crop to 90mm for example, you get a 90mm field of view with a 28mm f/2 depth of field for the distance you set your focus to, which is different than shooting a 90mm lens at f/2 and getting a 90mm field of view with a 90mm f/2 depth of field for that same focus distance. 

 

There is a website I often go to to understand the depth of field of each focal length which I suggest you play around with: 

https://www.dofmaster.com/dofjs.html

 

and if you don't want to do the test yourself there are a number of youtube videos explaining this, here's one to ilustrate this depth of field difference between 2 different focal lengths in the same camera for the same focus distance: 

 

 

Happy new year to everyone!

 

 

 

[Qwertynm]

vor 9 Minuten schrieb mca:

I just came accross this topic and it has been an interesting read.

Well, have you actually read it tough? The consensus was that a 90mm crop out of the Q3 looks nothing like a real 90 at f/2.8 in terms of depth of field but can be exactly the same in terms of field of view. The video and link you have posted are helpful for those still not getting it but I think many knowledgeable people already replied and actually DO get it, contrary to what you proclaim. 

[M11 for me]

vor 24 Minuten schrieb Qwertynm:

Well, have you actually read it tough? The consensus was that a 90mm crop out of the Q3 looks nothing like a real 90 at f/2.8 in terms of depth of field but can be exactly the same in terms of field of view. The video and link you have posted are helpful for those still not getting it but I think many knowledgeable people already replied and actually DO get it, contrary to what you proclaim. 

I agree. What you say is: Consider the equivalent aperture when you crop. When you look at an image taken with 90mm lens on an M camera at aperture approx 5.6 and compare this with an image taken with your Q3 at aperture 1.7 then crop to 90mm then the depth of field and the perspective will look the same. 

On the other hand you will have much more pixel in the photograph taken with M11 and 90mm than in the croped image from the Q3. But in many cases this is of no disadvantage. Depends what you want to do with that image. For the iPad or even on a bigger screen this is normally no problem. 

And do NOT take the Q3 for the "magic everything" camera. Zse it as the very versatile and light version when you want to travel or hiking. A Q you have always with you. 

And finally: Who the hell looks at photographs like Matt Day does in above video (what unrealistic images does he show to make his point). Be fair and acknowledge that your aperture is anyway set to 5.6 or 8. Probably this whole thing is a theoretical discussion. 

[Dr. G]

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It’s not a purely theoretical discussion.  I’m heading to a culinary event in Grand Cayman next week.  My go to setup would usually be the SL2-S with the 50 APO SL.  I can get relatively close with that lens to shoot product style food photos. I’m usually at or close to the minimum focus distance.  Because I’m so close, I would usually use an aperture of f/4 to f/6.3 at 50mm and still get a nice out of focus area around my subject.  With the Q3 I can probably stay at a slightly lower aperture close up in order to get the same look if I’m using the 50mm crop lines (I don’t like the look of shooting very close up with a subject that fills most of the frame at 28mm).   Maybe I can use f/2.8 with the 28mm cropped to 50mm.  This should mean I can set ISO lower - which may or may not have an advantage because the SL2-S renders fairly clean at higher ISOs, plus I’m going to assume that cropping to 50mm on the Q3 may produce an image that appears to have more noise - but that’s a whole different discussion.  I will also be able to use a faster shutter speed, though, so it may all balance out.

Edited January 4, 2024 by Dr. G

[M11 for me]

Thank you very much. As you explain you are in a situation where you choose your settings very carefully. And of course you think of the focal length that will give you best results and you know what you want to do. In such situations everything matters. I appreciate.

[clasami]

vor 57 Minuten schrieb Dr. G:

It’s not a purely theoretical discussion.  I’m heading to a culinary event in Grand Cayman next week.  My go to setup would usually be the SL2-S with the 50 APO SL.  I can get relatively close with that lens to shoot product style food photos. I’m usually at or close to the minimum focus distance.  Because I’m so close, I would usually use an aperture of f/4 to f/6.3 at 50mm and still get a nice out of focus area around my subject.  With the Q3 I can probably stay at a slightly lower aperture close up in order to get the same look if I’m using the 50mm crop lines (I don’t like the look of shooting very close up with a subject that fills most of the frame at 28mm).   Maybe I can use f/2.8 with the 28mm cropped to 50mm.  This should mean I can set ISO lower - which may or may not have an advantage because the SL2-S renders fairly clean at higher ISOs, plus I’m going to assume that cropping to 50mm on the Q3 may produce an image that appears to have more noise - but that’s a whole different discussion.  I will also be able to use a faster shutter speed, though, so it may all balance out.

Stop thinking and just try it at home. Take a plate with food and shoot that subject in crop mode. Afterwards you will know exactly how the OOF areas look.

Me, I try to keep it simple. So I multiply the actual F-stop of the lens with the crop factor to determine how much DoF I might get. That's close enough for me.

Edited January 4, 2024 by clasami
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[Orguy]

If I use the Q cropped to 90 and compare it to a shot at the same distance with a 90mm lens, will the DOF look the same? Same aperture, more enlargement of the Q's 90mm crop so that the print size is the same as with the 90mm lens.

Does anyone here have examples of this?

[Qwertynm]

No, not the same aperture. It will look like a 90mm at F/5.6 (90/28*1.7)

[jaapv]

I think that this subject has been done to death in the previous dozen of threads. 

[Orguy]

6 minutes ago, jaapv said:

I think that this subject has been done to death in the previous dozen of threads. 

Yes, I know it has been discussed many times that I have seen. The reason I re-asked it is because I have read many long winded and sometimes contorted responses and a lot of disagreement as to the answer to my question. I see a lot of posts followed by, "no that's wrong." I hoped by asking it again, I could see if a consensus had been reached.

Even better, if someone could post shots comparing the two: 90mm lens at x fstop vs Leica Q cropped image to 90mm at this same f stop. I dont have a 90 mm lens or I would try it. Qwertynm, thank you, seemed to say, nope - you have to stop down the 90 mm lens to f5.6. But I seem to recall others say that's wrong.

[jaapv]

I have posted a 28 mm ,70 mm crop and 70 mm native ( albeit no Q but that makes no difference) at least 5 times if not more. 

[Qwertynm]

At this point it seems as if people just keep trolling and asking that same question over and over and over

[Orguy]

2 hours ago, jaapv said:

I have posted a 28 mm ,70 mm crop and 70 mm native ( albeit no Q but that makes no difference) at least 5 times if not more. 

I didn’t know that or I wouldn’t have asked.
 

Could you please point me to it?

 

No, I haven’t read every post here so I am not aware of all the content. I’m not trolling. I’m honestly asking for help in understanding this.  Please, everyone, be kind and helpful. 

[jaapv]

28 mm

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70 mm

cropped to 70 mm AOV

[thegobi]

The technical term for crop vs native lens debates reoccurring is ‘The cycle of confusion’.

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Hallo,

Look here: Leica Q

[Orguy]

Therefore, cropping the Leica Q f1.7 shot to 50mm means that our 50mm crop will have the depth of field of a 50/28*1.7 = f3. lens Having used 50 as my normal for many years, I remember f3. as not shallow DOF at all. f2 or f1.4 is significantly better, if shallow DOF is what I am after.

Even if Leica ever changes software to have the EVF show the full cropped image (i.e., the full view in the EVF corresponds to the cropping setting), we are still shooting with an f3 lens at it's shallowest DOF.

All the more reason for Leica to release a 50mm lens on the Q, or buy an interchangeable lens camera.

[jaapv]

There is more to photography than shallow DOF which is regularity used to camouflage poor composition. The original Leica aperture was 5 cm/3.5. 50/2.8 was the fast lens. As for the frameline system, users that come from an M prefer it in general. There are quite a few reasons that I don’t want a Q, but these are not part of them.