EF and EFS, FF, Crop camera

If anyone is having trouble with the concept of a crop camera, just imagine taking a "full frame" 5D and applying some masking tape to the outsides of the sensor so that only an area the same size as a "crop camera" sensor is left exposed.

The resulting images will be exactly the same as any crop camera image.

You could mount 3rd party crop lenses( Sigma, Tamron, etc) to the 5D and the the image circle would cover the entire unmasked area.

Canon EF-S lenses would have to be modified to fit and because they extend further into the mirror box area. The full frame mirror can contact the rear of the element as it swings up at certain focal lengths or focus distances. Again, the image circle would cover the entire unmasked area.

Whether the crop is applied before or after taking the image, the results are the same.

stevewf1 wrote in post #17885402
It can be confusing. I have a 7DII and a Canon EF-S 10-18mm lens. The lens really does have a 10-18mm focal length, but I'll never "see" it that way on my 7DII. It'll always look like a 16-29mm lens on that camera. And to confuse things even more, I can't use my 10-18mm EF-S lens on a full-frame camera so that it can be a true 10-18mm lens...

What is a 'true (fill in here any FL) lens?!"

I previously wrote in this thread:

If I mount a 24mm lens on these different bodies, at 10' shooting distance a 10' tall subject is a 24mm image on the focal plane in ALL formats!!!

• I will capture 54% of the subject's height on the 4/3 format (13mm of the 24mm image)
  
• I will capture 62% of the subject's height on the APS-C format (14.9mm of the 24mm image; also 1/1.6 * FF, a 'crop')
  
• I will capture 100% of the subject's height on the FF format (24mm of the 24mm image)
  
• I will capture the entire subject plus 80% of its height in the surroundings on 645 format (43mm around the 24mm tall subject image)
  

Any FL mounted on any format simply has a AOV and FOV which is determined simply by the size of the film/sensor at the film plane. NO lens ever has a 'true' behavior, it solely is dependent on the body it is mounted on. With a film camera like a Mamiya RZ67, I can mount a single lens on the body, and via the removeable film backs I change the frame size in use...the AOV/FOV changes, yet the lens never changes. There is no single 'true (fill in here any FL) lens'.

This discussion reminds me why the 11-24 F 4.0 EF is such a beautiful thing. It gives you typical ultra wide coverage on a 1.6 crop, and it gives you super duper insanely wide on a 24x36 camera. If one shot both 1.6 crop, and 24x36mm format, it fills a double duty nicely (at a price). Would I buy one if I only shot 1.6 crop-oh heck no! I might be dumb, but I'm not stoopid

Unfortunately, with the way I use my Tokina 11-16, it produces just about the same results on my croppers and FF. Sigma used to make a 12-24 that was FF capable, and was one of the widest FF zooms at the time. I use the 11-16 on the 7D2 and the 1.4x TC + 11-16 on the FF today, as I currently don't have any EF glass wider than 24mm.

The 11-24 EF sounds very interesting to me, but is WELL outside my budget.

TeamSpeed wrote in post #17885703
The 11-24 EF sounds very interesting to me, but is WELL outside my budget.

Way outside my budget too, and I don't have any 35mm format bodies I could mount it on anyway, but I did get a chance to have a look through one last year at the photography show at the NEC. It was truly amazing. I flipped it around to portrait orientation, and could see my knees (I'm a wheelchair user), while holding the camera pointing horizontally! I wish I could have got a few shots with it, as it was on a 5DS at the time.

Alan

The good thing for you is on a crop you can grab the sigma 8-16mm if you want crazy wide- close to the equivalent of the 11-24mm, but can be bought for like $400