Brenizer with a crop sensor

amolitor

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This pops up from time to time, so I thought I'd take a few moments to pull together some remarks.

The Brenizer Method is, essentially, just using a little sensor to re-create a bigger one. You nail the lens down, and then wave the sensor around behind it taking multiple exposures, until you've patched together a bigger-sensor look. Now, you can't actually fix the lens in place, but you do your best.

So, general remarks:

- DO NOT ALTER FOCUS
- DO NOT ALTER EXPOSURE (meter the scene, then go manual to "lock" exposure)

Just make your multiple exposures behind your "as fixed as possible" lens.

With a crop sensor:

- DO NOT use an "equivalent length" lens. If you want that 85/1.8 look, you need a 85/1.8. The 50/1.4 is going to look like a 50mm lens on a medium format camera, which is also a thing, but not the thing you want.
- DO take twice as many shots. Your sensor has half the area of the full frame ones. You need twice as many exposures to make your "virtual sensor" be the same size.
 

Overread

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Thread re-opened, the former argument has been removed in its entirety in the interests of preserving the site as a place for discussion of photography and photographic methods. The forums are here to discuss and debate photography and are not a platform for drama or personal/petty squabbles between members. Any attempt to resume the former argument will result in time outs for those members.

I think you've explained it in a confusing manner and it might be simpler to say that you fix the focus and settings on the camera and lens and then move the complete DSLR setup around (rather than fixing the lens) to get the series of shots to stitch together, unless this is a different method to the one I think it is.




And resuming the interest in discussion, you say you nail the lens down and then move the sensor around behind it - I can see how that works in a technical sense, however I can't work out how you can move the sensor around behind the lens without removing the camera from the lens, at which point with the increased lens to camera distance necessary to let you move the camera around surely the focusing and frame will be a nightmare to sort out?
 

480sparky

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I've always been under the impression that the technique is quite like stitching a panoramic from a series of images. Preferably, said multiple images are taken with the nodal point of the lens in mind.

Use a telephoto lens, opened to a large aperture, to create a shallow depth of field. But take multiple images across the scene a stitched together to create a wide-angle image.

Net result: A wide FOV you would expect with a wide-angle lens (say, 28 or 24 or 20mm), but with a razor-thin DOF only a telephoto lens can create.
 

Robin_Usagani

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Just shoot it close to the subject and shoot really tight (fill the whole face on your framing). The longer the focal length, the better the result IMO because you have less distortion on the side of the frame. It is fine if you move the sensor a tiny bit. Just pick a position (standing or crouching) and stick with it. The stitching process will actually stretch and shrink your frames to fit together. Dont worry too much about the sensor size.. just think of it as you have a super fast wide lens that you will never see in production. (faster than an f/1) hah.
 
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amolitor

amolitor

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Well, you don't LITERALLY hold the lens fixed, and move the sensor, but that's because the two are kinda nailed together (and also there are issues with the lens' image circle etc etc). If you COULD move them separately, does it become obvious that you can make a "medium format" or "large format" or "any format you want" by moving the sensor up and down and left and right and taking lots of pictures, while the lens stays perfectly still and un-messed-with?

I think it's a useful way to think about it. If you imagine it in those terms, a lot of the questions that naturally pop up answer themselves easily.

I think of it as if the lens cast a big image on the back of the camera, and you moved the sensor around to capture chunks of that, and stitched those together to rebuild that big image on the back of the camera.

Maybe it only works for me? I dunno. It makes a lot of stuff seem "obvious" to me, but as a mathematician I have to be careful, because when I say "obvious" I usually mean "I can't think of any other way to explain it"
 

Robin_Usagani

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If you COULD move them separately, does it become obvious that you can make a "medium format" or "large format" or "any format you want" by moving the sensor up and down and left and right and taking lots of pictures, while the lens stays perfectly still and un-messed-with?

Sure... if you have a big enough lens that could project the image to all sensor positions :).
 
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amolitor

amolitor

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Anyways, the whole point of my OP was to help people out who are trying to do it with a crop sensor.

With the wrong mental model, you might well say "Ok, I'll use an equivalent length lens, say, 50mm, and follow the method as described in such and such a tutorial" which will work fine -- to produce essentially the effect of a full frame camera, or maybe a 645 format camera, with a 50mm lens on it. This is a bit disappointing, when the "look" you're hoping for is 85/1.8 on a 6x7.

You want the look of an 85/1.8? You gotta use an 85/1.8, no way around it, that *I* can see.

You want the look of 6x7? You gotta get enough pixels captured to actually fill 6 centimeters by 7 centimeters of sensor area, with suitable overlap for stitching. This is where you can cheat with multiple exposures and stitching.
 

480sparky

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If you COULD move them separately, does it become obvious that you can make a "medium format" or "large format" or "any format you want" by moving the sensor up and down and left and right and taking lots of pictures, while the lens stays perfectly still and un-messed-with?

Sure... if you have a big enough lens that could project the image to all sensor positions :).

Think of a common housefly's eye.
 

Benco

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Not sure why my question got cleaned off along with all the bickering...

:scratch:
 

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Not sure why my question got cleaned off along with all the bickering...

:scratch:

It was simpler just to nuke everything and give the thread a fresh start - you can repost your question :)
 

Benco

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Fair enough, Amolitor PM'd me an answer anyway. I just asked to clarify how the Brenizer method actually worked and that's been pretty well discussed on here how.
 

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