sergio

amfoto1 Loc: San Jose, Calif. USA

Whoever told you that is a doofus who doesn't know very much about camera gear. Ignore them.

There are no focus issues or issues of any kind, for that matter, using an EF lens on a crop camera.

The only thing is that you bought and paid for a full frame capable lens, but are only "partially" using it on a crop sensor camera. So, in a sense you aren't getting "full use" out of the lens you bought (hence, [i]if available[.i], an EF-S lens of similar range and quality can offer a smaller, lighter, less expensive alternative to an EF lens).

HOWEVER, with many lenses the crop means you're using the very best part of the lens... the center of many lenses has more resolution, better sharpness and less chromatic aberration and distortion than the corner or edges. The APS-C camera crops away the "worse" parts of the image area.

Great thing about Canon APS-C DSLRs is that they can use BOTH EF and EF-S lenses.... This gives you a huge selection to choose among.

Note: The DSLRs (both full frame and APS-C) cannot use the EF-M lenses (for Canon M-series, APS-S mirrorless cameras) and cannot use the new RF lenses (for EOS R full frame mirrorless). On the other hand, the mirrorless cameras CAN use EF and EF-S lenses (adapters are required).

Toment Loc: FL, IL

All this is true. But you CANNOT use EF-s lenses on full frame Canons.

Architect1776 Loc: In my mind

They have a crop sensor so it does not matter.

Toment Loc: FL, IL

Just a warning; it might be where the confusion started 👍

Architect1776 Loc: In my mind

No confusion as the camera in question uses ALL EF and EFs lenses.

MidnightManiac

I shoot a lot of sports and my 7DII is my body of choice. Love my 70-200 f4L...for outdoor sports. For indoor use a Tamron 70-200 f2.8.... Think that body is best for action sports...I've tried my 5DII and it just isn't right for action....

ccook2004 Loc: Rockledge FL

Thank you to all the UHH members who answered this question. I have had my Canon 7d 2 for a few years and have 4 L lenses I have had wonderful results with all except the 100mm (it gives me fits sometimes). The person who told me this was the teacher of an Advanced Photography Class. He also is a Canon guy. The question I asked was about some focus issues I have sometimes and his answer was that I shouldn’t use EF lens on a crop camera. I didn’t think it made sense because I have had great success with them especially my 100-400 II. But sometimes the photos are not as clear as I would like. I think he was just blowing me off. I recently started using BBF and am pleased with that. Thank goodness I asked here. I do want a full frame camera in the future but not right now. No more classes with this guy.

Architect1776 Loc: In my mind

dsmeltz Loc: Philadelphia

Except the new EOS R.

dsmeltz Loc: Philadelphia

If you can wait a year or two for a FF body, I think there will be an affordable FF mirrorless that will be awesome by then.

Architect1776 Loc: In my mind

And when adapters from second party makers all your FD, FL and Canomatic R lenses as well as the original Leica thread lenses.

dsmeltz Loc: Philadelphia

This is why I, as an APS-C Canon shooter, am so excited about the EOS-R. Well this and AF to f/11!

ccook2004 Loc: Rockledge FL

I think I will do that. No hurry.

Architect1776 Loc: In my mind

Yes, this was a brilliant move by Canon.
Especially making ALL the EF and EFs 100% compatible and enhanced with the control ring adapter to 120% compatible with higher performance.
It was amazing to see how they solved a tough problem. But that was because they had the brilliant EOS system to build from that has been all electric from the beginning 1n 1987/88. You just can't find that compatibility anywhere else.