Ultra Wide Zoom Lens Clarification

[HokeyHokey]

This is a really dumb question, but are "Ultra-Wide Zoom" lenses the same as an ultra-wide angle? I see standard wide angles are very short, but no short ultra-wide angles. The only ultra-wide anything I see is ultra-wide zoom.

[jrhoffman75]

The operative word is "zoom" You can have an ultrawide zoom lens that goes from say 11-24mm (11mm being ultrawide). Fixed focal length lenses are less versatile so there are fewer manufacturers making them. Laowa makes a 12mm fixed FL lens for Canon RF bodies. 

[HokeyHokey]

If I'm trying to capture an entire room, should I go with fixed? Does the zoom lens being longer significatly affect how much I'm able to get in the frame?

[kvbarkley]

A Zoom at 11mm will have the exact same field of view as a prime at 11mm. So unless your prime is significantly shorter than the zoom, it will not affect the field of view.

[HokeyHokey]

It's a difference of 2.6 inches in length. Will that reasonably affect getting what's on the far sides of the camera in the frame, or is it negligible?

[jrhoffman75]

Lens length is irrelevant. If the lens is designed for the body then the image will cover the entire sensor. The length of the lens is controlled by the number of elements and the spacing. 

If you have a full frame camera and are considering a non-Canon lens you need to be sure that the lens is designed for a full frame body. Many third party lenses are designed for APS-C bodies ( think Rebel). They will fit on a full frame body but you will get a somewhat circular image.

[HokeyHokey]

Do you have any ultra wide angle lens recommendations for an APS-C EF mount camera? It's my most likely incorrect understanding that the ultra wide zoom is for far away objects which I don't need as it's for real estate photography.

[rs-eos]

Don't pay attention to the physical length of the lens.  Each lens has a rating for focal length.  Either a single value (prime lens) or a range of values (zoom lens).  The focal length and size of your camera's sensor will determine the field-of-view.   To capture as much as possible within a frame, use an ultra-wide on a full-frame camera.

[jrhoffman75]

A 10-18mm zoom lens, for example, at the 10mm setting, will give the same image as a fixed focal length 10mm lens. The zoom is more versatile since sometimes 10mm could be too wide. 

I suggest you look at the Canon 10-18mm zoom. 

[ebiggs1]

Lenses use tricks to make the claimed FL. This makes the physical size of a lens different looking. But that is all just different looking and has little to do with actual FL. One problem with a Rebel or any APSC camera is getting really UWA lenses.  You typically gain on the tele end and pay for it on the UWA end. My current favorite WA zoom is my AT-X 16-28 F2.8 PRO FX. Although not a UWA it is a very good lens at a very reasonable price. If you need a  UWA zoom the Canon EF-S 10-18mm f/4.5-5.6 IS STM Lens is your best go.