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Lord Vetinari
Jun-28-2005, 10:44 PM
On the other photographic site I post in a fad has just broken out for using reversed small focal length lenses on the front end of a larger lens (don't think the larger lens has to be a macro lens). This gives a further magnification factor. In my case reversing an old pentax Kmount F1.7 50mm lens onto my 105mm EX macro lens seems to give me a ratio of about 2.5:1 i/o 1:1. The drawback is the DOF seems to be about 0.5mm and the focus is about 10 to 20mm infront of the reversed lens. As you can imagine it's a bit hard not to spook the insects when you have to get that close- but it can be done.
Some people are just holding the reversed lens- others like me use a lash/up connector made of cardboard tubes- others use proper screw mounts made out of filter holders.
Here's some examples of the results.

First to give an idea of scale a strawberry

http://homepage.ntlworld.com/j.valentine/CRW_5096c.jpg

A few flower centres

http://homepage.ntlworld.com/j.valentine/CRW_5074c.jpg

http://homepage.ntlworld.com/j.valentine/CRW_5116c.jpg

A grass flower

http://homepage.ntlworld.com/j.valentine/CRW_5079c.jpg

Some insects

A parasitic wasp ?

http://homepage.ntlworld.com/j.valentine/CRW_5028c.jpg

A midge about 4mm long

http://homepage.ntlworld.com/j.valentine/CRW_5090c.jpg

A small spider

http://homepage.ntlworld.com/j.valentine/CRW_5038c.jpg

A small fly (about 8mm long in total) with a smaller passenger behind it's head

http://homepage.ntlworld.com/j.valentine/CRW_5103c.jpg

tmlphoto
Jun-29-2005, 08:02 AM
Very interesting set of images. I think it becomes increasingly difficult to obtain a pleasing aesthetic at such high ratios. I think I may get a set of extension tubes to play with. Any experience with them?

Higgmeister
Jun-29-2005, 08:49 AM
I've been wanting to put my reversed 50mm on front of my 100mm macro to see what it will do, now I know. Those are incredible. I used the reversed 50mm on my Sony V3 and had a miserable time focusing, especially on bugs. Have you tried to take enough frames for stacking the shots to increase the apparent DOF. Unfortunately I have focus problems (still getting used to the equipment) just using the 100mm, let alone the reversed 50mm added on. Kudos for shots well done:thumb.

Thanks for sharing these Brian,
Chris

Higgmeister
Jun-29-2005, 08:54 AM
Very interesting set of images. I think it becomes increasingly difficult to obtain a pleasing aesthetic at such high ratios. I think I may get a set of extension tubes to play with. Any experience with them?
I've had a chance to play with my Kenkos extension tubes and my 100mm macro. It decreases the lens to subject distance, but also increases magnification. It also appears to narrow the DOF. The tubes have all the contacts for AF and no glass to introduce additional distortion. I really like extreme macros so they are worth while for me. The narrow DOF doesn't detract for me. They won't get the magnification a reversed lens will though.

Hope this helps a little,
Chris

DRT-Maverick
Jun-29-2005, 09:40 AM
I've got a teleconverter 2x, which should give me a 2:1 ratio, not as good as a 2.5:1, but decent I hope. I could doublestack.

Lord Vetinari
Jun-29-2005, 10:35 AM
Very interesting set of images. I think it becomes increasingly difficult to obtain a pleasing aesthetic at such high ratios. I think I may get a set of extension tubes to play with. Any experience with them?Hi Thomas- Think you are right about the images-they are very hard to get in the first place (at least with handholding the camera) and are often not very pleasing. I've had a wastage rate of about 5 shots out of 6 doing these.
No experience with extension rings I'm afraid.
Brian V.

Lord Vetinari
Jun-29-2005, 10:37 AM
I've been wanting to put my reversed 50mm on front of my 100mm macro to see what it will do, now I know. Those are incredible. I used the reversed 50mm on my Sony V3 and had a miserable time focusing, especially on bugs. Have you tried to take enough frames for stacking the shots to increase the apparent DOF. Unfortunately I have focus problems (still getting used to the equipment) just using the 100mm, let alone the reversed 50mm added on. Kudos for shots well done:thumb.

Thanks for sharing these Brian,
ChrisThanksChris,
you are right it is very hard to focus on moving items anyway. Not sure it is actually worth it, but have had some success with spiders- I'll post them later.
Re focus stacking- I have enough trouble getting any shots in focus with this method Lol. Might try it with a dead or chilled insect and a tripod though.
Brian V.

Higgmeister
Jun-29-2005, 10:43 AM
I've got a teleconverter 2x, which should give me a 2:1 ratio, not as good as a 2.5:1, but decent I hope. I could doublestack.
How's the clarity and DOF with the 2x converter? Also, what happens to our lens to subject distance, shorter or longer and approx. how much change?

Thanks,
Chris

DRT-Maverick
Jun-29-2005, 11:07 AM
How's the clarity and DOF with the 2x converter? Also, what happens to our lens to subject distance, shorter or longer and approx. how much change?

Thanks,
Chris
No actual change that I've noticed in focal distance. The DOF is still left at F3.5-32, which is the default on the 180mm macro. The Stop is bumped an entire stop though, so you'd have to set it at ISO400 to get what you would at ISO200. I didn't notice any reduction in quality. Those butterfly shots I took earlier were with the 2x Teleconverter.

Lord Vetinari
Jun-29-2005, 11:47 AM
Two more shots using the add-on revesed lens
Brian V.

http://homepage.ntlworld.com/j.valentine/CRW_5191c.jpg

http://homepage.ntlworld.com/j.valentine/CRW_5217c.jpg

pathfinder
Jun-29-2005, 12:22 PM
On the other photographic site I post in a fad has just broken out for using reversed small focal length lenses on the front end of a larger lens (don't think the larger lens has to be a macro lens). This gives a further magnification factor. In my case reversing an old pentax Kmount F1.7 50mm lens onto my 105mm EX macro lens seems to give me a ratio of about 2.5:1 i/o 1:1. The drawback is the DOF seems to be about 0.5mm and the focus is about 10 to 20mm infront of the reversed lens. As you can imagine it's a bit hard not to spook the insects when you have to get that close- but it can be done.
Some people are just holding the reversed lens- others like me use a lash/up connector made of cardboard tubes- others use proper screw mounts made out of filter holders.


B&M calls the adapter rings for mounting a normal lens reversed, so the front element of both lenses are facing each other, a Macro Coupler. They come a large variety of sizes - 49 t0 49, 58-77mm, etc. Search B&H for "GBMC" and a whole bunch of them pop up. They are inexpensive - $7.95 each.. Buy several :D :D Or $5.00 from camerafilters.com They will allow the mounting of a 50 or a 28mm lens reversed on a 50, 100, or 150mm lens. The mag ratio will then be about the ratio of the focallengths .

Noveflex makes an adapter that lets you reverse an EOS lens on a Canon body but still retain the EOS electrical connections and thus the ability of the lens to communicate its data to the attached body. Here is the link
http://www.novoflex.com/english/html/macro_accessories.htm

Lord Vetinari
Jun-29-2005, 12:28 PM
Thanks for the info Pathfinder,

I'm still trying to make up my mind whether it's worth doing in the first place, but if I decide yes, will look into the links you gave.
Thanks again
Brian V.

didymus
Jun-29-2005, 12:52 PM
Fascinating images, what sort of lighting setup are you using?

Lord Vetinari
Jun-29-2005, 12:59 PM
Fascinating images, what sort of lighting setup are you using?Thanks Didymus.
Using the same flash setup as in the pic of the rig here
http://forums.dpreview.com/forums/read.asp?forum=1031&message=13654064
(except of course the reversed mounted lens is not shown).
Because of the postion of the flash and homemade diffuser- it still works fine with the other lens on the front.
Brian V.

Aussie_bluey
Jun-30-2005, 03:49 AM
Very cool group of macros, well done.
:clap :clap :clap :clap :thumb :thumb :thumb :thumb
Tim

Lord Vetinari
Jun-30-2005, 04:03 AM
Very cool group of macros, well done.
:clap :clap :clap :clap :thumb :thumb :thumb :thumb
Tim
Thanks Tim
Brian V.