woody123 0 Posted June 21, 2011 Hello, I'm not familiar with auto-iris lens internals. If one were to disassemble an Auto-Iris Lens, is there a fully functional Manual-Iris Lens inside? I'd like to remove the electronics and use the Auto-Iris lens Manually on a Digital Camera. Any pitfalls or problems to watch for? Is this possible or a pipe dream? Thanks, Woody Share this post Link to post Share on other sites
Nimrod 0 Posted June 21, 2011 Manual lenses are very inexpensive on ebay, no need to trash a good one to make a cheap one. Share this post Link to post Share on other sites
woody123 0 Posted June 21, 2011 thx nimrod, can I take your answer to mean that, yes, there's a functional manual-iris lens inside the auto-iris shroud? Share this post Link to post Share on other sites
rory 0 Posted June 21, 2011 Yes, just remove the pieces that make up the iris, or cut or leave the cable disconnected (never tried that personally). However your camera must support electronic/manual IRIS or it will be white out in the day time. What type of lens is it? On what type of camera? Share this post Link to post Share on other sites
woody123 0 Posted June 21, 2011 Appreciate the info Rory, Local security company going out of business, they're dumping a couple used wide-angle computar auto-iris lenses in fine shape. I'd like to use them on a DSLR in manual mode with a C-mount adapter. Manual Computar/Pentax-Cosmicars are typically used on these DSLRs, but wasn't sure if the guts of an Auto-Iris was essentially the same and could be adjusted by hand when disassembled. I don't know enough about the internal working of the auto mechanism. Is it just a motor assembly that sits outside of the lens barrel? Attached to the lens by shallow screws? Glued? Regards, Woody Share this post Link to post Share on other sites
rory 0 Posted June 21, 2011 No cant adjust it by hand. Its a collection of thin curved blades, internally. Its not possible to manually adjust it with your hands as its inside the lens, and it would likely damage it. The lens would need to have its own level for adjustment (manual iris lens) or the camera would need to provide an electronic iris. One might be able to cut the wire and then trigger it manually somehow but I cant say for certain and thats more work (=money) than just buying a manual iris lens. Auto Iris Eg http://www.shutterstock.com/pic-3160510/stock-photo-aperture-blades.html Share this post Link to post Share on other sites
woody123 0 Posted June 21, 2011 Ah, got it now Rory. Thanks. The last picture, especially. I have several standard, permanently broken, photography lenses here, torn apart to examine. My imagination had an auto-iris lens the same as a standard manual lens, but with a motor mechanism attached externally to the lens barrel, driving the iris(aperture.) ...but the manual iris adjustment ring is entirely 'replaced' with the auto motor mechanism. Share this post Link to post Share on other sites
NotoriousBRK 0 Posted June 21, 2011 You can't adjust it manually, but the iris is typically DC-Driven. You *could* build a little device with a 9V battery and a potentiometer to control the lens externally. You used to be able to buy a lens testing device like this in many places, but I haven't seen one for sale in several years. All the DC iris lenses I've seen default with the iris closed. Share this post Link to post Share on other sites
Soundy 1 Posted June 22, 2011 I believe most AI designs just have a gear on the motor, that then drives a ring gear on the iris... IN THEORY one could remove the motor and just turn the gear with a small screwdriver or something. But that would be tedious in the extreme, I would expect, and I believe most cameras will have the iris spring-loaded to close if there's no drive signal, so you'd have to lock it in place somehow. I think the DIY drive controller would probably be a better bet. Share this post Link to post Share on other sites
SEANHAWG 1 Posted June 22, 2011 I agree with Nimrod. Check ebay. You can probably find one for less than $10. For the time it will take to jack with this you could get one sent to you in the mail quicker and less painful. Share this post Link to post Share on other sites
rory 0 Posted June 22, 2011 If it were the AI on a M13 lens (eg. Bullet or Dome) i could help test that as I have a bunch of those lenses here with broken IRIS .. (self inflicted while messing with the IR cuts). No full lenses lying around to dissect though, they are very different from the M13's as far as the AI goes. Share this post Link to post Share on other sites
timeee 0 Posted August 18, 2011 Hello, I have a also question about the autoiris... I have a Fujinon objective with an autoiris and I want to control the iris manual with an external switch (not with the videosignal of a camera). Does anyone know how to get this work? thanks timeee Share this post Link to post Share on other sites
mike_va 0 Posted August 18, 2011 I have a ton of autoiris lenses here, and I have a Watec camera that does not do autoiris. I bought one of the sockets from digikey, and put a resistor in series with the 12V supply to prop the iris open. I think I used 2 200 Ohm resistors (I can check if there is interest), easy enough to try with a pot though. Probably only good for setting it open, I doubt if it would be stable over temp at some intermediate setting. If you already have a good auto iris lens and you're trying to get a camera to have a higher shutter speed it can be useful also. Share this post Link to post Share on other sites
