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09-07-2011, 06:20 AM   #61
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QuoteOriginally posted by Nass Quote
Quick dumb question from me, no way to get CiF working with tubes AND reversed lens?

Thanks
CIF will work with tubes or reversed lens. The camera mount contacts may need to be shorted out by touching shiny metal (use sandpaper to remove black paint if necessary.)

09-07-2011, 06:34 AM   #62
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So both together should also work? Hm, think I'll try it

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09-07-2011, 07:56 AM   #63
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QuoteOriginally posted by Nass Quote
Quick dumb question from me, no way to get CiF working with tubes AND reversed lens?
CIF doesn't care what kind of optics are sitting on the camera. CIF just depends on focus confirmation; it only requires that 1) the mount contacts are appropriately connected or shorted, and 2) the lens delivers an in-focus image. So yes, CIF will work with a reversed lens on tubes.

Remember that reversal brings your working distance down to ~45mm on a prime lens. DOF will be very thin. That close, the range that focus confirmation and CIF have to work in is very thin, and will work in the center of the image. Keep that in mind as you frame shots. Good luck!
09-07-2011, 08:45 AM   #64
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Thanks Rio Anything to make shots like this easier is gratefully appreciated. Holding your breath to try and focus not just on a fly but a part of a fly's eyes, with a depth of field measured in parts of a mm, whilst crouching in an unsustainable angle, looking through a nearly dark viewfinder, holding a ridiculously extended reversed lens overshadowed by an absurdly sized homemade diffuser isn't exactly conducive to the greatest success rate in the world .

09-07-2011, 02:17 PM   #65
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Ok. Interesting. Took me about 2 hrs, a bunch of googling, a bunch of filing and lots of attempts to even get CiF working. Not constantly, somewhat predictably, with reversed lens and tubes. Clearly CiF likes its light and wide open apertures. I know I digress but that green hexagon does seem to have a little bit of a mind of its own. Anyhow, it'll be interesting to use outside. I'd hope and be delighted if it'd help, but I can't help feeling a bit sceptical as the little I've done outside always tends to be at 5.6/8/11 ish and that might reduce the light too much. But maybe the overall brightness will alleviate that. Guess I'll just see.
09-07-2011, 03:55 PM   #66
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I've found that the cutoff for CIF is around f8-11 effective aperture. Some longer lenses need a bit more light than f/8, like around f/7. Some shorter lenses require less light than f/11, like around f/13. But those are pretty much the limits for stopping down.

Effective Aperture: EA = NA + (M+1) where NA is Nominal Aperture (where the ring is set) and M is magnification. So at 1:1 you lose two stops of light; 2:1 loses three stops; etc. T'ain't no free lunch. Ratz. That's partly why I keep saying that lens reversal is for studio work. Aim some lights at the subject, no problem!

Yes, a bit of filing is needed, to scrape off paint from the mount-reversal adapter to (safely) short the mount contacts, for CIF to work. What DOES NOT work is a bit of metallic tape on the adapter. Its thickness just guarantees that the adapter will jam on the mount.
09-07-2011, 04:06 PM   #67
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QuoteOriginally posted by RioRico Quote
I've found that the cutoff for CIF is around f8-11 effective aperture. Some longer lenses need a bit more light than f/8, like around f/7. Some shorter lenses require less light than f/11, like around f/13. But those are pretty much the limits for stopping down.

Effective Aperture: EA = NA + (M+1) where NA is Nominal Aperture (where the ring is set) and M is magnification. So at 1:1 you lose two stops of light; 2:1 loses three stops; etc. T'ain't no free lunch. Ratz. That's partly why I keep saying that lens reversal is for studio work. Aim some lights at the subject, no problem!...
Note typo correction EA = NA x (M+1) times not plus

Also a similar equation for diffraction limit except divide by (m+1); that means if mag is 1:1 then diffraction softening will set in at 1/2 the f-stop you'd expect. That means don't push f-stop too much; f:10 is a LOT from a sharpness standpoint.
09-07-2011, 10:03 PM   #68
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QuoteOriginally posted by newarts Quote
Note typo correction EA = NA x (M+1) times not plus
Duh, yes, you're exactly right. That's what I get for keyboarding whilst asleep. Thanks.

09-08-2011, 10:01 PM   #69
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I opened this thread a while ago and I forgot to say that I tried all your suggestions and got some cool pictures
thanks again
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