lens reversing

It means putting the lens onto the camera the wrong way round.
You need an adaptor or reversing ring I think

When the lens is reversed it acts like a macro lens


At least thats my understanding of it:D
 
twist said:
http://www.flickr.com/photos/larajade/353212395/

Can also use 2 lenses and a coupler.
Click to expand...

Yes you can do some impressive microphotography quite cheaply with a couple of neat tricks. If you put a telephoto on your camera, then reverse a wide angle onto it, this gives you a magnification onto the sensor that's the ratio of the focal lengths. So if you have a 300mm tele and 30mm wide, you get 10 times mag.

To do this on the cheap, I simply bought a couple of Chinese Cokin P series adaptors off ebay - one for each lens - at a couple of quid each. I then simply bolted (clamped actually in my case) them together flange to flange. This then screws into both filter threads to mate the lenses face to face.

MicroPhotogrphary_Rig.JPG


The other challenge is that the wide angle, being off-camera, will be stopped fully down by default. This makes the already feeble light transmission pretty much zero. So you need an aperture ring too to open it up. (Alternatively you can knock one up on the cheap again simply by using a rear lens cap, cutting a hole in the end and fitting a small pin to the inside that slides the aperture tab round when you fit it to the lens.)

Even with an aperture ring you need a bright yet cool light source to focus and a powerful flash to get sensible exposures - and a good solid tripod is still critical.

Given all that though, for about a fiver and some basic engineering skills you can get some pretty good results. Here's a shot of a Daphnia from our garden pond that's magnified about 17 times onto the sensor.

Daphnia_Tail.JPG


Good fun if you've the time and patience...
 
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