5D and 14mm, 15mmFE and Vignetage

Good Afternoon,

Have you got problems of vignettage with this configurations ???

Can you shown your pictures ???

Thanks a lot ..

Cheers..

laurent

I have not used the 14mm, but the Sigma 15mm does not vignette noticablely.

I can confirm William's observations on the Sigma 15mm FE. Fine and dandy

Martyn

I have not used the 14mm, but the Sigma 15mm does not vignette noticablely.

<{POST_SNAPBACK}>

Not sure which "setup" you are referring to but I just got back from Belize with my 5D and the Canon 14mm.

I have no vingnette issue with my UK-Germany housing and the dome but I still apparently have some issues with the dome centering.

I did the calculations to determine the entrance pupil location (53mm from the face of the lens) and UWE provided me the calculations for his dome and we centered the dome very very close to that point.

I take quite a few WA closeups when there ain't much else and I have significant blurring in the corners. I haven't done any "real" testing at smaller apertures in a well lighted pool but the issue may indeed be more to do with the depth of field, virtual image and the recti-linear character of the lens.

Thanks a lot for yours messages..it's very important for me...

I'm going to work with a subal housing because i've already bought dome....

Have you got pictures about ??

Some people said to me, the 14 mm started vignetting at f8 !!???....

See you...

Laurent

Here are three shots taken with the 14mm. Un cropped and un-edited.

you can see that there is no vignetting but on the shot with the silversides in the cut you will see softness in he corners.

also, if you look at the brain coral you see it in the right hand corners.

This is puzzling to me and I'm such a rookie that I can't explain it...

The other photos are in separate posts following.

By the looks of that f/8 brain coral I'd have to say "Myth Busted" to the vignetting nay sayers.

I don't see vignetting as an issue with underwater images most of the time. If people do find it to be intrusive there's always the vignetting control in Adobe Camera Raw, or even better DxO.

Martyn

Well it is hard to make any conclusions from a picture at F/8. Vignetting is never (or almost never) a problem when the lens is stopped down.

At F/2.8 it is possible there could still be significant vignetting. But then if you are allways going to be shooting at F/8 then it does not really matter though.

Very true William, it was more that Laurent had heard that "... the 14 mm started vignetting at f8". It certainly doesn't appear to start there. As you say, it could start at larger apertures. From reviews it would appear that although there's a little at f/2.8, it's basically gone by f/4. Not bad really.

Have a great weekend,

Martyn

Just to re-focus this discussion, usually vigenetting in UW photos has to do with the port selection and not the camera-lens.

I don't have this camera but I haven't heard anyone say that these lenses vigenette on a full-frame camera like the 5D. Both these lenses were designed for film so they should be OK.

Make sure you are using a big dome for wide angle lenses and ask Subal. The Sigma is almost 180 degrees on full frame and very short so this could be an issue. For example, the problem William had with Ikelite ports and the Sigma 15mm on the 5D as I remember it was that the standard port for the Sigma was ok for cropped digitals but not for the full-frame 5D. It vigenetted. The WA dome for the Nikon 10.5mm (also 180 degrees) was too short for this lens. So he needed the new 8" dome port to solve it. And If I remember it worked great.

So anyway, check your dome.

WRT soft corners. Soft corners on WA is often a problem esp. with WA zooms and rectalinear lenses. We forgot about this problem when we went to cropped sensors on older full frame lenses and the soft corners were cropped out. But I'm with William, usually this is only a problem a wider apertures. F8 should be good to go. Maybe its subject/camera motion? Maybe the worm was sucking in? What was the shutter speed? Did you use flash? The worm to me looks more blurred than the brain coral.

Here is William's explanation:

http://www.photography.willandsam.com/Revi...dome/index2.htm

Hello,

I've just come back from holidays..

Thank you for all yours messages.....

Follows recommandations, i'm going to ask to subal..i've the big dome....

But, with 14 mm and 15 FE sigma, i don't know yet my choice....!!!!

Cheers...

Laurent