15mm lens question

[Olivier Staiger]

a question about 15mm wide angle lens

on a crop camera such as the Canon EOS T2i / 550D , the 15mm results in 24mm equiv.

thus, the 10-22 lens , set at 15mm, will give 24mm equiv.

the 15-85mm lens, at 15mm, should give the same view, right ?

but what about the DIAGONAL FISHEYE 15mm 2.8 lens from Canon or Sigma ?

is it the same result ? or is the view even wider despite the 15mm branding ?

if anyone here has both a 15mm/2.8 diagonal fisheye, and either the 10-22 or 15-85 lens, could you please shoot an image with each , at 15mm, to compare ?

 

[Darren Addy]

Good question, as many people simply assume that the focal length to field of view relationship is constant. Not so when you get into fisheye territory. Fisheye will have a much greater diagonal FOV, but you will (of course) have fisheye lines instead of rectlinear lines.

Can't speak to your specific lenses, but in general here is more than you probably wanted to know about the subject.

 

[Chris Gullikson]

I have a Sigma 15 2.8 fisheye and use it on my Canon crop camera from time to time. It does produce a very wide angle photo with less of a fish eye look then a full frame camera, but it still has moderate field curvature.
I would often times "defish" the image using a photshop plugin (Canon RAW will do this) to remove the field curvature. I enjoyed this combo for its extreme wide FOV, sharpness and of course its an F2.8

June 10th 2004 - 15mm fisheye and original Canon Digital Rebel

 

[Darren Addy]

By the way Chris, that is still one of my favorite storm images of all time. If I took a shot like that I could die happy.

Regarding defishing, while it would be a workable solution in some cases, I think I'd much rather get a rectilinear wide (especially since we are talking about 15mm and very good rectilinears go to 10mm) than hassle with defishing in post (I would think that would get old quickly, when it could be there in the original image with the right lens choice). Also, regarding defishing you might want to compare some of the various software options out there before deciding which is best. Some software seems to do a better job than others and there are reports by some users of a change edge sharpness or even the introduction of CA that wasn't visible in the original (maybe we should call it pseudo-CA).

If superwide-wide is your objective I honestly think you need to be on a "full frame" digital (and I say that as a APS-C guy myself). The crop costs you too much real estate. You can get a first version 5D for around $800 now.

 

[Chris Gullikson]

Darren, thanks. That shot was a lifer for me...but I do wish I had my 5D Mark II back then!!!

I think I bought the 15mm fish back when the super wide APS-C lenses were not yet available or maybe too costly for me at the time. defishing is a pain and I am sure you lose something in the conversion. If I had to do it again and shot primarily with a crop camera, I would surely go with a 10-22 - which I have rented several times and find to be a great lens.

I have played with the 15mm fish on the full frame a couple times...180 FOV makes for a dramatic and unique view, but I would rather have a 16-35mm.

 

[Jason Foster]

Darren, thanks. That shot was a lifer for me...but I do wish I had my 5D Mark II back then!!!

Don't we ALL!

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[Gene Moore]

Darren, thanks. That shot was a lifer for me...but I do wish I had my 5D Mark II back then!!!

I think I bought the 15mm fish back when the super wide APS-C lenses were not yet available or maybe too costly for me at the time. defishing is a pain and I am sure you lose something in the conversion. If I had to do it again and shot primarily with a crop camera, I would surely go with a 10-22 - which I have rented several times and find to be a great lens.

I have played with the 15mm fish on the full frame a couple times...180 FOV makes for a dramatic and unique view, but I would rather have a 16-35mm.

Chris, about defishing, I have used it in PhotoshopCS5 and it works, but not all is perfect. Recently I used my EOS 15mm 2.8 while shooting the meteor shower in northern Arizona (freezing my face numb). The results are that it blurs the bottom corners as it must "pull" the horizon down to flatten it. The way to get around it is to center the horizon then it's flat.

By the way, that shot will go down as one of the all time greats in chasing history, at least in my opinion. I was on the back side of the cell trying to get into position..... didn't make it....LOL, but that's chasin isn't it.