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Trevor Rees

Canon versus Nikon

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I botched doing the link above. :D Too many open windows!!! :D So I have re-attached the straight FE shot (i.e., not de-fished) for comparison with the two above. :blink:

Tom

post-3540-1130302271_thumb.jpg

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For rectilinear lenses - YES.

 

But, for fisheye lenses, the  formula is slightly different.

 

See this explaination by Bob Atkins for a little more detail if you are interested.

Surprising but its not exactly so, at list according to the specifications in B&H:

Canon EF-S 10-22mm: Angle of View 107.5-63.5°

Sigma EX DC 10-20mm: Angle of View 102.4-63.8°

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Ingvald,

 

I know this is probably a stupid question, but your shot of the plumose, that was in Norway??? They are rather prolific in the pacific northwest (puget sound) area of the USA.

 

I love them, they make a wonderful macro study, I didn't realize they were on the other side of the world but I guess that makes sense. I imagine your water temps are about the same.

 

They are rather beautiful in the emarld waters of puget sound.

 

Stuart

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Framing helps a lot, here is an example:

 

whalebone.jpg

 

This was not de-fished. If you keep the straight lines (horizon in this case) close to the center of the lens, the distortion is less apparent. I have another shot taken from the same spot here somewhere else (bad sign, can't find it, I have to get myself organized) where I framed the horizon higher in the picture to avoid the blown out clouds on the top left; the distortion is *a lot* more apparent.

 

Alternatively, keep the straight lines in the diagonal to minimise distortion. They are called diagonal fisheyes after all:

 

johanfaulbaum_04_08_bw.jpg

s/s Johann Faulbaum, Jarfjorden, Norway. Nikon F80, Sigma 15mmFE.

 

While I suppose you cannot possibly shoot a steel ship with a FE without showing any distortion (although this is pretty unnoticeable in Alex's image), in wooden stuff it does not matter that much since the wooden ships tend to be more shapely anyway. In this one I have even used the distortion to exaggerate the imminent destruction of the wooden hull (probably does not tell much to those never been to this site, though...):

 

keulakuva_04_08.jpg

Elisabeth Osborne, Tryhalsskär, Hanko, Finland. Nikon F80, Sigma 15mmFE. Viz around 3 meters.

 

timo

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Ingvald,

 

I know this is probably a stupid question, but your shot of the plumose, that was in Norway??? They are rather prolific in the pacific northwest (puget sound) area of the USA.

 

I love them, they make a wonderful macro study, I didn't realize they were on the other side of the world but I guess that makes sense. I imagine your water temps are about the same.

 

They are rather beautiful in the emarld waters of puget sound.

 

Stuart

 

The plumose shot is taken in Norway, it is very common over here. Have some more shots that I posted her:

http://wetpixel.com/forums/index.php?showtopic=10232

 

Should think the temprature is about the same, since it is about equally to the north. Her the temprature is from 1 to 20*celsius

 

As you wrote they are beautiful, and an exellent motive.

 

As my boss say, "There no stupid questions, only stupied anwers"

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Metridium are common in Alaska too! :blink:

Tom

post-3540-1130390281_thumb.jpg

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They can attain lengths exceeding 0.5 meter! :blink:

post-3540-1130390440_thumb.jpg

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Great shots Ingvald!

 

I envy you the 10.5 ….

 

Back to the original topic. I have a Canon 20D, and when I bought it I was hoping for a fullframe fisheye. I’ve been mailing both Canon and Sigma R&D departments, but none as given me any positive replies on a fullframe fisheye for the 1.6 sensor. I’ve also posted on DPreview, but no one has any information on a fullframe fisheye. The only thing I’ve found so far is a very vague rumour that canon was planning a fullframe fisheye that someone overheard at a party…. Not much to rely on…

 

So what to do now?

 

One option is the 5d, but it’s a big investment and I would have to have a new housing. Another option is to go Nikon, but then I have to get everything including lenses. And that would be a defeat, since I’m the only Canon shooter here in Bergen, contrary to Ingvald and others ïŠ

 

So please Sigma and/or Canon, I want a fullframe EF-s fisheye!

 

 

 

Harald

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Sigma make an 8mm circular fisheye for full frame use. I assume that the image circle must be about 24mm (width of FF) so this lens should work on a smaller format digital with a very wide but cropped image- has anyone actually tried it?

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Sigma make an 8mm circular fisheye for full frame use. I assume that the image circle must be about 24mm (width of FF) so this lens should work on a smaller format digital with a very wide but cropped image- has anyone actually tried it?

 

In a recent issue of Kamera-lehti (Camera magazine) of Finland, there was a test of a Belarussian 8mm circular FE lens called Peleng (http://www.kievcamera.com/product.php?ID=14) used with a Nikon D70. The sample images show only minor cropping in the corners, almost none along the short sides but obviously a fair bit along the long sides of the image. From the samples in the magazine, I would say the horizontal coverage must be in the ballpark of 170 degrees.

 

The bottom image (of skydivers) in the Kiev Camera page linked above looks very much like the one presented in the magazine review with Nikon D70.

 

How the image circle in this lens would compare to the Sigma 8mm, I have no idea.

 

timo

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I enjoyed reading all the above reports - since I got my 10.5 fisheye yesterday (no port yet).

Any ideas what a 2xTC would do to the pic underwater? Ye I know it is a weird question - but since digital U/W is so new, I am braking all the rules... and some work beautifully!

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Teleconverters can't be used with lenses wider than 80mm (or something like that) as they produce black corners in the images (vignetting). I think that if you put one behind a 10.5 you will have an image with large black areas in the corners and sides.

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Not on land - I find that the fishbowl effect is rather non existing - but havent played with it enough - just curious what it could do underwater. I also use my 2xTC very succesfully on my 60mm macro

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Let me see if I got that right, the 2x TC does not produce vignetting on the 10.5? I would never imagine that!

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Here are some interesting facts about teleconverters:

 

1. Teleconverters accomplish their task through the use of optics to further magnify the object to be photographed. This means you are inserting more optical interfaces between the object to be photographed and the film in your camera. Each optical interface that you insert in the light path has the capability of reducing image quality - NO teleconverter can improve the image quality that was possible with the lens alone at a shorter distance, it can only enlarge the image and degrade the image to some extent.

 

2. As the focal length increases, so does the apparent 'camera shake' associated with the longer focal length - you will need to take this into account by setting your shutter to a higher speed or resort to using a tripod to reduce the effect.

 

3. The minimum focusing distance that was possible with the lens alone changes minimally. If your 100mm lens alone will focus down to 18 inches and you attach a 2X teleconverter, you now effectively have a 200mm lens that focuses down to 18 inches + the physical length of the teleconverter.

 

4. The amount of light entering the camera body through the lens-teleconverter combination is reduced. In the case of your 100mm/4 lens and a 2X teleconverter, your effective lens is now a 200mm/8. Since less light (actually ¼ as much) is entering the camera, you must compensate for it. In SLR cameras, the meter reads the light entering the body, so proper exposure is still obtained by reading your camera meter as always. However, less light means that exposure times may need to be increased through the use of slower shutter speeds - again requiring the use of a tripod and perhaps a remote shutter release. You may have to switch to a faster film to offset this effect also.

 

5. In general, teleconverters are designed for short (200mm and less) or long (300mm and greater) lenses and can not be switched back and forth. In general, you can expect more image degradation with a 2X teleconverter than with a 1.4X teleconverter. In general, 3X teleconverters are nearly worthless because of image degradation.

 

6. Always read your lens specification sheet before attaching a teleconverter - damage may occur otherwise.

 

What TC do you have? Nikon doesn't recommend use of theirs in anything wider than 70-80mm, but I think that's for 35mm (full frame).

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I actually thought if was a rather stupid idea (and probably is) to put a 2xTC on a 10.5 - I mean really - it DOES sound stupid - but since I try everything, I found that it is actually ok - NO vignetting. Not to say that it is a good idea, but then whaever you do different is never a good idea in some ppl's books. I have therefor decided I have to try everything for myself. For the macro lens - the 60mm just didnt get close enough - I like tiny tiny things (amphipods) and voila! it worked!

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