Robber fly "head shot"

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Bruce Williams
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Post by Bruce Williams »

Wonderful clean image with beautiful colour balance - would love to see a 1280x1024 uncompacted version of this image.

Bruce

dave_putty
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Post by dave_putty »

I agree with all this is superb
Nikon D80

Cyclops
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Post by Cyclops »

DaveW wrote:SD,

There are two reasons for reversing lenses. A conventional camera lens (usually a fixed focal length standard lens) can be used like a multi-element supplementary close up lens by reversing it on other lenses using a coupling ring to join the two filter threads together.

Secondly, reversed lenses can be used direct on the camera or on bellows or tubes using a lens reversal adapter that has the lens filter thread on one side and the camera bayonet on the other. When you use a lens closer so that its film/sensor distance is greater than it's lens to subject distance you are moving from the parameters it was originally designed for. So put simply turning it round so the end designed to be close to the film/sensor now faces the nearer subject and the end that was designed originally to be further away from the subject faces the larger film/sensor distance tends to restore the optimisation of it's design.


DaveW
Theres a fact often overlooked when using reversed lenses tho.
Most are asymmetrical, that is omne end is bigger than t'other,especially wide angles. So although it may be f2.8 the nbormal way this could drop to f4 or below when reversed.
This is called the pupillary maginifcation factor or PMF. If your usiong TTL flash of course this is taken into account but if youre setup is manual it needs factoring in.

If you use film of course you can usually get away with it!
Canon 5D and 30D | Canon IXUS 265HS | Cosina 100mm f3.5 macro | EF 75-300 f4.5-5.6 USM III | EF 50 f1.8 II | Slik 88 tripod | Apex Practicioner monocular microscope

DaveW
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Post by DaveW »

Easy to find out if the lens is symetrical or not. With the lens off camera stop the lens down so the diaphragm is just showing, measure the size of the diaphragm hole showing in the rear element, then in the front element. If these sizes are not more or less the same then it is unsymetrical and if you use anything other than TTL metering or TTL flash metering a pupillary magnification factor needs to be applied. Most decent close up and macrophotography books usually have tables for this (Lester Lefkowitz's book for instance)

If your lens doesn't have an aperture ring to stop it down, only buy close up lenses in future for reversal on bellows etc that have for macro photography.

If all the systems lenses will not stop down using the aperture ring when removed from the camera, either buy into a better system that does, or simply use enlarger or other manufacturers lenses reversed on bellows etc for such magnifications!!!

DaveW

Cyclops
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Post by Cyclops »

I think with most 50mm lenses youre OK, the diferenceis minor and as most are digital these days its easy to correct.
Of course in the old days 50mm lenses, the standard lens sold with a camera, were symettrical, and had relatively slow apertures (f2 being the norm,like my Zentih 58mm lens), but as things moved on it was usual to have the max aperture as f1.8 or 1.7. Anything wider(f1.4 or ,if you could afford it, f1.2) and you need to account for it

Its mainly wide angles that need factoring, as a 28mm f2.8 will have a very small back aperure compared to the front,leading to a much darker image, but giving about 2X mag reversed, which is cool.
Reverse it onto a 100mm and you get 100/28=3.5X! You will get vignetting tho!
Canon 5D and 30D | Canon IXUS 265HS | Cosina 100mm f3.5 macro | EF 75-300 f4.5-5.6 USM III | EF 50 f1.8 II | Slik 88 tripod | Apex Practicioner monocular microscope

Anupam Basu
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Componon 28mm/f4

Post by Anupam Basu »

Magnificient. Simply awesome.

I use that schneider lens and can vouch that it is a true gem. Picked it up for $20, I believe. Makes me laugh when people spend big bucks to get magnification.

-A

Alex Paul
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Joined: Wed Dec 20, 2006 6:45 am
Location: Bahamas

Post by Alex Paul »

Fantastic shot.... Thanks for the focus stacking inspiration..... Guess it is finally time to give it a go........Alex

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