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500mm mirror @ 1/640sec, tripod

Nice looooong shot! That lens is a popper!

you are having fun with your new lens........... good capture, and I like the B&W treatment.......

Nice one and no doughnuts that I can see

sirhc55 wrote:Nice one and no doughnuts that I can see

I remember shooting cars on the expressway on a damp night from the end of Ridge street North Sydney looking towards the bridge......... the doughnuts from using a 500mm lens gave some interesting effects.......

I’m with you bp - I have always found the doughnut effect, especially when applied to city wet nightscapes, fascinating

I've been checking online for one of these mirror lens, they look like fun, and fairly cheap to get that extra bit of length.. this shot has just increased my interest. Nice work.


I take it that Mirror lens can have 'doughnut' noise or bokeh ? (just guessing from the comments).

Noise comes from using digital high iso .......... bokeh comes from len's..........just to keep it simple..........

EDIT: Google is your friend.....

Well where do doughnuts come from ? The Doughnut patch ?

Alpha_7 wrote:Well where do doughnuts come from ? The Doughnut patch ?

They are from the way the Len's are made......... a combination of glass len's and mirrors.........Highlights in the background give a circular shape hence they are called doughnuts..........

Alpha_7 wrote:Well where do doughnuts come from ? The Doughnut patch ?

More information here........

http://www.photozone.de/3Technology/lenstec5.htm

Google is your friend.......

Thank you very much Big Pix, I apologise if you thought I was being rude, I went back to the doctors and I'm on much stronger medication.. seem to have left me in a funny / less than normal mood. As I have had an appetite in days, all this talk of doughnuts set me off.

Thanks for the link..... and your patience.

Alpha_7 wrote:Well where do doughnuts come from ? The Doughnut patch ?

From the mirror design. Examples of the bokeh can be found here.

Thanks Trent. Nice. Pick on my pics Hehe

I still get a laugh out of Phillippb's comment in that thread.

Back on topic.
I do like the candid at the top of this page. The B&W works great on it. Very nice work.

I assume this is the same lens, or atleast similar.

http://cgi.ebay.com.au/TAMRON-SP-500-8-MIRROR-LENS-NIKON-CANON-PENTAX-ETC_W0QQitemZ7568342496QQcategoryZ707QQssPageNameZWD2VQQrdZ1QQcmdZViewItem

yes...... but it is full of fungus...... sometimes this is not able to be cleaned out of a len's.........

That and the postage is atleast the same as the reserve price... pity about the fungus... the prices online seem to vary drastically for Mirror lens.

Alpha_7 wrote:Well where do doughnuts come from ? The Doughnut patch ?

The donut shaped OOF blur comes from the central obstruction of catadioptric lenses. Being a greenhorn around here I really hate to contribute critical remarks in the, uhh, critique forum, but this shot is a prime example for why mirror lenses are of limited use for general photography. The out of focus rendering is plain horrible. This is not the photographer's fault of course. It is simply an physical limitation of the lens design.

Observe how contrasty lines, when out of focus, turn into "tubes" (for lack of a better word) with sharply defined edges and a blurred interior. In some places the background seems as sharp as the the subject. The image has its share of classic donuts, too, wherever there is a point-shaped highlight in the OOF areas.

I'm actually quite a fan of catadioptrics (esp. the Maksutov-Cassegrain variety), but as a hobby astronomer, not as a photographer. But then, in astronomy there aren't any out of focus subjects...

Bad bokeh isn't limited to mirror lenses though. Some of the most revered tack-sharp Nikkors have it too, like the 85/1.8. That's why people spend more than twice on the 85/1.4 although it doesn't seem any sharper. It just delivers nice smooth OOF blur, which gives great 3-dimensionality to a photograph. A couple of friends of mine have mortgaged their earthly posessions to switch from a Nikon to a Leica system, for the same reason.

To sum it up, I have no critique to offer from a creative standpoint, just a technical rant. I hope I didn't offend anyone.

Cheers
Steffen.

No offense, thanks for the information.