Effect Of 1.6x Crop Sensor On Lens Compression

[Garbz]

Mixing apples and oranges only get us an fruit salad. :mrgreen:

Depends on what you consider apples and oranges. I would definitely consider switching a 50mm lens for a 300mm lens and leaving all other things equal a completely different picture, whereas switching the 50mm for a 300mm and compensating by moving further away much more true to the original intent.

Or to think about it this way, did I completely give up using my 50mm on my APS-C because it's now too long for 3/4 length portraits? Heck no, I just started standing further away from my subject to take the photo.

 

[Dao]

Here something to think about.

Case: Take a photo of a coffee mug sitting on a kitchen counter.
Photo1: 100mm lens on 1.6x crop body compose -> shoot -> photo resize
Photo2: 100mm lens on full frame compose -> shoot -> crop the photo -> photo resize.
Photo3: 100mm lens on full frame walk closer compose -> shoot -> photo resize.

Assuming at the end, the size of the coffee mug on all 3 photos are the same and composition are some what the same. And final photo size are the same.

As far as perspective distortion concern, photo1 and photo2 should be the same, but not photo3.



So I believe the effect of 1.6x sensor on lens compression. Technical, no effect. However, if the camera to subject distance change due to image composition as a result of crop factor, you may say yes. But really, that is not because of the lens, it is the photographer.

 

[clanthar]

crop factor doesn't affect compression... that's only affected by focal length... crop factor just makes it so u see less in terms of the frame...

\The relative size and spatial relationship between objects in a photograph can only be altered by moving the camera.

Joe

um

thats not true

if i stick my body on a tripod, stick a 100mm prime on it, have 2 objects, 1x 20 ft away and 1x 40 ft away...

when i change to a 24mm prime, both objects will look farther away, and they will look farther apart than with the 100mm

if u move the camera so that the closer object is the same size in both, then then 24mm will make the second object look farther away and smaller than the 100... am i misunderstanding you?

yes I think you may be misunderstanding and you are wrong.

Here's the error:

"when i change to a 24mm prime, both objects will look farther away, and they will look farther apart than with the 100mm"

Yes the objects will look further away but they will not look further apart.

You are correct in your second assertion which is what I said; moving the camera will alter perspective.

stick you camera on a tripod with a 100mm lens on it and photograph a scene with a sign in it.

don't move the camera but switch to a 24mm lens and take another photo and compare the two.

The photo taken with the 24mm lens will have more content and if you made 8x10 prints of both photos everything in the photo from the 24mm lens will be smaller. HOWEVER the relative size and spatial relationship between objects in the two photos will be identical. Print each photo so the sign is the same print size in both and the photo from the 100mm lens will be an exact match to the center section of the photo from the 24mm lens.

The only way to change perspective is to move the camera -- with a stationary camera changing lenses only crops the content.

Joe

 

[clanthar]

Crop factor has nothing to do with it.
Understanding Camera Lenses

Unless you're trying to get the same picture in which case when you bolt your 50mm on your crop factor camera then you need to step further away from the subject and the result is more compression in the final picture.

If you step further away from the subject then you are not trying to get the same picture. It's not the same picture if the perspective is altered. If you're trying to get the same picture you'll put the two different format cameras in the same place. Then use lens focal length (eg. normal lens on both) to keep the content the same.

Joe

 

[Hardrock]

Is this the compression you are talking about. Look half way down at the 2 water bottles. That is focal length compression (at least to me). The camera is obviously not in the same spot but the pink water bottle is very close to the same size in all three. Hope this helps.

 

[djacobox372]

The physical placement of the camera in relation to the subject is the ONLY thing that affects "compression." Focal length and sensor size has absolutely nothing to do with it!

This is a fact, and not debatable. EOT