APS-C - Red Dot / White Dot

E

elusive1

Member
OK,

I'm a real idiot. I have a Tamron 17-50 APC lens for several weeks.

I'm at work so I don't have my camera with me, but I think I have been aligning it with the red-dot on my camera when mounting. I didn't read the manual well enough, and I realized now that I was suppose to be aligning the white dot with the white dot.

The strange thing is the lens seems to work fine in every way. Sharp focus, fast autofocus.

I was looking at the lens several days ago to inspect for dust, and I didn't notice any damage to the lens and the camera seems to be working fine.

Did I royally screw up somehow?

Also, since I think I've been mounting it to the red-dot, does that mean that you can use APS-C lenses on Full Frame cameras like the 5D? I know there's a vignetting issue, but aside from that, will they work?
 
PerroneFord said:
As far as I know, they only fit one way. If your camera is working, you've been doing it fine.
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This.

The manual is undoubtedly referring to the kit lens, which might have a different looking alignment mark than your lens.

Does your lens have both a red dot and a white dot?
 
elusive1 said:
My lens Tamron 17-50 VC only has a white dot.

Thanks for the responses.
Click to expand...
Just to be safe you should probably make sure to align it correctly when you get home.

In response to the last question from your original post, this is what wikipedia says:

"Canon designers have taken steps to ensure it is physically impossible to mount EF-S lenses on EF-only cameras. This is because the increased proximity of the lens to the sensor means that on full-frame sensor or 35mm film EF cameras the lens itself would obstruct the mirror's movement and cause damage to the lens and/or camera. While it is possible to modify the lens such that the physical obstruction is removed, allowing for mounting to EF mount cameras, the rear of the lens would still obstruct the mirror. An additional reason is that the lenses produce a smaller image circle of even illumination (circle of no vignetting). An EF-S lens alignment mark is indicated by a small white rectangle, whereas the EF employs a small red dot. The lens will insert into the body when the alignment marks on each are matched, and the lens can then be rotated and locked into the operating position. EF-S camera bodies have both EF-S and EF alignment marks, while EF bodies have only EF marks. Some have reported success attaching EF-S lenses to full-frame bodies with the use of an extension tube; however, this does not eliminate the vignetting problem, and also removes the lens's ability to achieve infinite focus."
 
If a lens doesn't fit, just keep pushing and twisting harder. I will get in there eventually.



*I kid, although it pains me to see people try with brute force.
 
there is a red dot and a white square on the Camera, Dont worry about the White sqare on the camera, Use the white DOT on the Lense and Align it up to the red dot on thne camera...
 
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