Question about the crop-factor...

[Ikinaa]

Soon (end of the year), I will buy myself a DSLR, just waiting what the photokina brings new.
So I become more and more interested in the technique involved.
There are TC1.4x and TC2.0x (or more?) for the DSLR you put between body and lens.
Is there something like a WC1.3 (wide converter) or WC1.6 for DSLRs or will there be one or is it optically possible?
So that a DSLR with a 1.3 or 1.6 crop factor will come down to a 35mm equivalent, like a full-frame?
The vignetting shouldn't make any problems, as most lenses were designed for 35mm?

[Aylwin]

Nope. No such things as wide converters. You just have to get a lens wide enough for your needs taking the crop factor into account.

[hmhm]

There are "wide-angle converters" available for video cameras and some point 'n' shoots. These typically "screw-on" like filters. I've heard of people using them on DSLR lenses, though I can't imagine the image quality is very good.

But as already mentioned, there's nothing specifically included in the Canon DSLR product set for this purpose.
-harry

[Ikinaa]

There are "wide-angle converters" available for video cameras and some point 'n' shoots. These typically "screw-on" like filters. I've heard of people using them on DSLR lenses, though I can't imagine the image quality is very good.

But as already mentioned, there's nothing specifically included in the Canon DSLR product set for this purpose.
-harry

I got a WC for my G3, such a one may help on a DSLR when really needed.
Is there a technical reason why there isn't a WC for DSLR to screw between body and lens or isn't there simply the need of it?

[Aylwin]

Technically, it's possible. Some EF lenses use 58mm filters. If your WC is 58mm then you could simply screw it on just like a filter. While there are some good quality WCs out there, the image quality will no doubt suffer. Still, if you already own a WC then I guess there's no harm in trying. It might save you from having to buy a wider lense... at least for awhile.

[CyberDyneSystems]

Is there a technical reason why there isn't a WC for DSLR to screw between body and lens or isn't there simply the need of it?

Yes.. all you would get is a very large dark circle around the image that the lens itself creates..

A "wide converter" between the lens and camera can not make the image that the lens creates any wider than it is when it leaves the rear of the lens.. so a "wide converter" at the rear would simply make a huge vignette.

[stuartf287]

There was a post on this forum (or on dpreview) some time ago in which someone used a screw-in WA converter designed for a point-and-shoot on an EOS digital SLR. The results which were posted didn't look too bad. I'd think the main problem would be finding a WA converter of the correct size to screw into the front of a regular EF lens. The converters are probably small in order to fit on the lenses of the G-3 (or whatever), since those cameras have relatively small sensors and correspondingly small lenses. The size problem, along with quality degradation, seem to rule out this "solution" in most cases.

[stuartf287]

http://forums.clubsnap.org/showthread.php?t=86714


The poster apparently used an Olympus WA converter with the 24-85 EF lens, showing that it may be possible to use such a converter with a regular EF lens. The question is whether the results are worth it. The converter apparently costs about $180 without step-down ring.