Canon 1.6X crop conversion to full frame

Does anyone have a web site to compare the 1.6X crop camera to full frame cameras lens comparison. Thank you..

Not sure what you mean.. could you reword that?

Hi, what I'm trying to find out is the lens difference using a crop camera 1.6X compared to using a full frame 35mm camera.

do you mean which lenses you can use on each type of camera, or how the field of view changes between the two types of bodies? Sorry for not understanding..

BLEITH1965 wrote in post #5601739
Hi, what I'm trying to find out is the lens difference using a crop camera 1.6X compared to using a full frame 35mm camera.

On 1.6 crop the corners are sharper, you can get away with cheaper lens. Also there is a DOF difference.

The moment I went to Full Frame i sold all my non L lens and sigma glass.
Hope that helps.

What is the DOF difference. That's got to be my question is there a chart that compares the two? Thanks..

its not that complicated. You will get better image quality over all with the full frame cameras, but with the 1.6x you can get away with cheaper lenses because you might not need the longer ones. The DOF difference has to do with the 1.6x of the focal length. A 50mm 1.2L lens will have a certain amount of DOF, but when you put that lens on a 1.6x, it becomes a 76mm f1.2L lens, which will have less DOF due to the increased focal length.

Canon Soldier wrote in post #5601889
its not that complicated. You will get better image quality over all with the full frame cameras, but with the 1.6x you can get away with cheaper lenses because you might not need the longer ones. The DOF difference has to do with the 1.6x of the focal length. A 50mm 1.2L lens will have a certain amount of DOF, but when you put that lens on a 1.6x, it becomes a 76mm f1.2L lens, which will have less DOF due to the increased focal length.

Are you saying that a given FL lens at a given aperture will produce less DOF than the same lens on a FF camera?

It sounds weird, but its true if this DOF calculator is to be believed.

I don't know optics, but DOF appears to increase when used on a FF body.

Canon Soldier wrote in post #5601889
The DOF difference has to do with the 1.6x of the focal length. A 50mm 1.2L lens will have a certain amount of DOF, but when you put that lens on a 1.6x, it becomes a 76mm f1.2L lens, which will have less DOF due to the increased focal length.

Completely incorrect.

As has been cleared up numerous times in previous threads, it's a 1.6x crop factor. All the crop factor does is, well, exactly what it says it does. It crops the image of the lens, doesn't magnify it as a teleconverter does. Therefore, focal length is NOT affected by the camera, only field of view.

So, to go with your example, the 50 1.2L on a 1.6x will still have the DOF of a 50mm lens at equivalent distances and apertures, but slap that lens on a 1.6x crop and it will have an equivalent FOV of an 80mm lens on 35mm format. DOF is completely unaffected, again, assuming the same subject distance and aperture obviously. I'm also not quite sure where you got the figure of 76mm.

Now if you aren't shooting at the extreme ends of the focusing range (not at the MFD or at infinity), the FF will usually have less DOF since you have to move closer or zoom in for an equivalent FOV to the crop body. So as you can see, it's quite the contrary to your claim, crop bodies typically have more DOF.

Calzinger wrote in post #5602030
it's quite the contrary to your claim, crop bodies typically have more DOF.

Yes and no. Its true that if you move closer in order to get the same FOV that the FF will have less DOF.

BUT, the same lens at the same distance on a 1.6 crop and FF camera will give more DOF on the FF. I guess its just apples and oranges at that point though, because like you said, you're now dealing with two different FOV's so your image wouldn't be the same.

edit: correct me if this is wrong. I'm basing my argument on the calculations from http://www.dofmaster.c​om/dofjs.html

TopGear1Ds wrote in post #5602099
Yes and no. Its true that if you move closer in order to get the same FOV that the FF will have less DOF.

BUT, the same lens at the same distance on a 1.6 crop and FF camera will give more DOF on the FF. I guess its just apples and oranges at that point though, because like you said, you're now dealing with two different FOV's so your image wouldn't be the same.

What's the point in comparing two images of different FOVs? The question was regarding DOF, and in everyday shooting, the FF will typically have less DOF. I would think that you would frame your shot similarly regardless of format. That's why I used the word typically, as in everyday shooting.

And why would the FF yield more DOF at equivalent distance, aperture, and focal length? Would the images not be exactly the same with the crop just having a shorter AOV? Speaking purely from an optics point of view, I would think they would be the same, but hopefully someone will dive in and enlighten me.

I wasn't disagreeing with you. You quoted my post, but did you read it?

you edited your post since I repsonded, so I'll add to mine.. I don't know why the DOF would be different. I had the same logic as you in my head, thinking that it should be the same. However, when I looked it up on a DOF calculator (I linked to it), the DOF chagnes as you change formats. I'd also like to know the reason. Hopefully when I wake up tomorrow morning, there'll be an answer here!

In theoretical terms, when all other variables are equal — focal length, shooting distance, size of print, viewing distance — the APS-C image has a greater amount of magnification, therefore it has a shorter depth of field than the 35mm-format image.

In practical terms, you usually get a shorter depth of field with the larger format, because you compensate for the increase in angle of view by reducing the shooting distance or using a longer focal length.

DoF is perception, not a constant property of an image.

FF will have shallower depth of field than 1.6x at a given FoV, not focal length. DoF remains the same whether it's 50mm f/2 on a 1.6x or on FF. What changes it the field of view so that the 50mm lens would give a FoV of an 80mm lens when used on a 1.6x but still have the DoF of a 50mm lens.