Photoclubalpha

Any comment on this lens? Appreciate if some photos can be shared. Is USD680 a fair price for a second hand unit?
http://www.dyxum.com/lenses/detail.asp?IDLens=66

Thanks.

Have you checked here.
http://www.dyxum.com/dforum/forum_posts.asp?TID=11341

Thanks Doc. I was thinking about seeing more bird shots...
I do notice that the bokeh looks a little bit weird especially on this shot:
http://farm3.static.flickr.com/2397/222 ... 4486_o.jpg

If a new Tamron 200-500mm can be bought at USD840, would it be a better choice than this lens?

Thanks.

Frankly I don't know Kelvin. I am targeting at either the 70-300 G SSM, or the 70-400 G SSM.

I'll start off with an example of how bad the bokeh can get. This is 100% crop. If you pixel peep the background you will find double-imaging all over the place. This seems to happen when the subject and the background don't have enough separation.


Here's another with similar problems.


For me, these are not typical; they are worst case.

Why do I live with it? Because I'm more interested in the birds than the bokeh, it's sharp, and it weighs less than two pounds and easily fits in my Lowepro Computrekker Plus mounted on an A700 with the hood on

Winston wrote:This is 100 % crop. If you pixel-peep the background you will find double-imaging all over the place. This seems to happen when the subject and the background don't have enough separation.

Was the image of the ... umm, falcon? hawk? ... the bird-of-prey taken hand-held with the image stabilizer on? This looks like the kind of bokeh you'll get when the image stabilizer has to work real hard to keep the plane of focus stabilized. For simple geometrical reasons, the shake cannot be compensated for at all subject distances equally so an image stabilizer at work actually can affect bokeh (no matter if it's in-body or in-lens) ... at least in theory. The jury is still out on the question if it actually can have a visible effect in real life ... but to me this looks like a typical example of image-stabilizer-induced nisen-bokeh.

-- Olaf

I guess nice or not nice is a very subjective term. But basically I find this bokeh pattern distracting. It has a "mirror bokeh" look.

The image of the Geater Kestrel was taken in Kenya with a bean bag placed on a motionless truck. I don't think SSS had anything to do with the bokeh.

It is typical of the lens. Many zooms produce the same 'wiry' defocused image because of the position of the aperture diaphragm in the optical design. There is nothing you can do about it but shooting wide open reduces the effect.

David

The SAL75300 (75-300) has the same effect. Hope hat 70-300 G or 70-400 G are not likewise.

Dr. Harout wrote:The SAL75300 (75-300) has the same effect. Hope hat 70-300 G or 70-400 G are not likewise.

My Sigma APO 70-300mm doesn't have this effect. I though the design between these two was similar?

kelvinyam wrote:...
My Sigma APO 70-300mm doesn't have this effect. I though the design between these two was similar?

It seems to me that some lenses are worse than others. The only Sigma APO examples I could find quickly are here:
http://www.dyxum.com/dforum/forum_posts.asp?TID=12148

They don't seem bad, but not what I'd call the best bokeh either. (The fences, for example, seem to have some double-vision going on...) Seems like I've seen a couple of examples from that lens that had a "busy" bokeh.

While I have noticed this busy bokeh in various lenses, it is worse when backgrounds have a lot of lines, like grass. This is probably a worse-case background. If I used my 55-200 with grass in the background, I'm going to expect it to look like this!