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10-18-2008, 08:54 PM   #1
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Opinions please.

I tried to test out my Vivatar 400mm f5.6 lens for CA and would like some opinions.
The lens is "as new" but there is no indication that it is multi-coated.

I have had the lens for 6 months or so and the first few images I took with it looked pretty good to me but i'm no expert. I took it out today for a few quickies and left the lens wide open, tried to get some shots with some contrast to check it out.

All of the shots are at f5.6, handheld, and Jpegs right out of my K100D Super.

1st shot is from about 100ft. and please excuse my focusing



75ft.



75ft. again



60ft. and I did not notice the squirrel until I looked at the image (I can see CA in the upper right hand corner)




Thanks as always,

Ray

10-18-2008, 09:05 PM   #2
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1st one there is some CA in the branches
2nd and 3rd look pretty sharp

try this out
The Online Photographer: How To Stress A Camera Lens
10-18-2008, 09:28 PM   #3
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Looks like the lens has potential. As you pointed out there is some noticeable purple/green CA in the 4th photo's high contrast areas, but you will need to take a wider range of images to see if it bothers you.

If you have a reasonably solid tripod and the lens has a tripod mount you could see quite an improvement in sharpness by using a remote and mirror lockup for photos. It can be a bit awkward for moving animals, but depending on your subject the extra quality may be worth the effort to you.

I have a Soligor 400mm f6.3 that I picked up cheap (no idea who the actual manufacturer was though) and find that stopping down to f8 through f11 cuts down on CA significantly on high contrast scenes, and the extra depth of field is also helpful when background separation isn't a priority. Using stationary objects like my tripod, fences, and trees (or other convenient rests) often helps quite a bit with steadying the lens.

I don't know how you're focusing, but my k10 indicates the focal point of the lens to be a fair distance in front of the actual focus point, which means that I have to go with what looks sharp in the viewfinder and ignore the focus confirmation.
10-18-2008, 09:39 PM   #4
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[quote=Steinback;370791]Looks like the lens has potential. As you pointed out there is some noticeable purple/green CA in the 4th photo's high contrast areas, but you will need to take a wider range of images to see if it bothers you.

If you have a reasonably solid tripod and the lens has a tripod mount you could see quite an improvement in sharpness by using a remote and mirror lockup for photos. It can be a bit awkward for moving animals, but depending on your subject the extra quality may be worth the effort to you.

I have a Soligor 400mm f6.3 that I picked up cheap (no idea who the actual manufacturer was though) and find that stopping down to f8 through f11 cuts down on CA significantly on high contrast scenes, and the extra depth of field is also helpful when background separation isn't a priority. Using stationary objects like my tripod, fences, and trees (or other convenient rests) often helps quite a bit with steadying the lens.

I just wanted to test it wide open for grins.

I will have a do-over with the tri-pod sometime this week.

Here is one more, neighbors truck at 290ft. and I can see some CA in the chrome.

I don't think it's bad for this lens (is it?)



Thanks again,

Ray

10-18-2008, 09:56 PM   #5
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I think the truck shot turned out quite well, the area in focus is sharp and even though there is some CA on the highlights I don't find it distracting.
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