[icy]

Not only is this possible, but I've made the mod to my camera. It takes less than 5 minutes to do, and less than 5 minutes to undo - although so far I have found NO reason to undo it.

> ...

Some of us old farts really get into taking a 21st century computerized camera and turn it a 50+ year old match-needle wonder.

Amazing! Perfect! I can't believe that my camera is simply tricked in less than 5 minutes

I use an aluminum strip from a cigarette pack. The strip has only one aluminum side so I need to fold it first. I have only one camera so there is no picture to show, but the steps are almost identical to newarts' one.

Thank you so much, Jim, newarts et. al.

[miv7]

Thank you very much, I do this trick on my K-x and it works perfectly.

[hnikesch]

I shorted the "A" pin on the body of my Km, I have 2 K-M lenses a Sears 135 f2.8 and a SMC 135 f3.5, I painted the areas on the bottom of the lenses to simulate the correct "A" contacts for the corresponding aperture range. What I found was metering was far from correct, I set the body at AV f8 and the lens at several apertures, wide open, f8, and f22 the exposure was over exposed 2 stops in all settings. Setting the body at EV -2.0 all exposures seemed to be correct.

Hans

I've done some additional playing and it seem the problem with K-M lenses is the travel of the aperture lever is not the same as on a K-A lens. When the body tries to close the lens down a number of stops from the wide open info from the contact matrix to the chosen aperture in AV mode it is done by a pre-determined travel distance of the aperture lever.

[JimJohnson]

The beauty of digital photography is you can run tests and figure this kind of thing out on the spot.

Back in the film days, most medium format studio photographers spent big bucks for a Polaroid back to get this kind of convenience. Even if you have to dial in an adjustment, having some kind of aperture value output makes full manual control a LOT easier. Prior to learning this pin-shorting trick, I felt I was going to be forced to go really old school and rely on my 36 year-old hand-held exposure meter and/or my equally old pocket size Kodak Master Photographer book with its several paper exposure calculators.

[icy]

I shorted the "A" pin on the body of my Km, I have 2 K-M lenses a Sears 135 f2.8 and a SMC 135 f3.5, I painted the areas on the bottom of the lenses to simulate the correct "A" contacts for the corresponding aperture range. What I found was metering was far from correct, I set the body at AV f8 and the lens at several apertures, wide open, f8, and f22 the exposure was over exposed 2 stops in all settings. Setting the body at EV -2.0 all exposures seemed to be correct.

The biggest challenge is to set right exposure when the pin is tricked. As I remember, the min/max apertures that the body sees is f/22 - f/1.2 (no matter the real physical lens is.) Using negative EV or a fix amount of speed shift would help, though the amount will vary and depend on the lens.

Here is again more fun. I almost can't express my ideas in English, but I will try my best: I cut off a small aluminum foil from a metal bottle of Tiger beer. This foil will be inserted into the very thin spaces between the lens and the body's mount. The foil doesn't conduct electric as it's painted specially. So if you want to short any pin, you just clean paint at the area associcated to the pin.

The picture will help (Original link: Home / Tag ShortContact | Di?u's FineArt)

# Detect the pin pattern (read this article Features and Operation of the Ka Mount). For example, for f/2 - f/16 you will need to short the pin R2 and the metadata pin

# Locate your contact area on the lens mount and add more spaces


# Create your contact foil


# Put the contact foil between the lens and the body's mount (Actually you can't mount the lens within this foil inserted; just mount the lens normally to the body; after that insert the foil to the very thin space between them.)




Other notes

1. If you need pattern metering, you need to short the meta data pin
2. The M42 lenses are very easy to trick: there is always a enough space for you to insert the foild and you can skip the 2nd step above.
3. Follow my instruction at your own risk!!! As you are going to cause physical changes on your lens mount, and you CAN'T REVERSE YOUR CHANGES. Only do the trick on old / obsolete mount, or M42 lenses
4. Please fix my English and make my posted better and understandable as my English is terribble
5. I successfully create my contact foils that help the body to see the correct min/max aperture for the following lens. (And I can use pattern metering for all of these lenses)
   1. MC Pentacon 1:1.8 50mm (M42)
   2. Super Takumar 1:1.4 50mm (M42)
   3. Rikenon 1:2 50mm (K-mount)
   4. Helios 44m-4 (M42)

I don't like beer much but this time I found beer is really good for lens,at least the way it helps to trick my Pentax K-r And, I don't see the need to pay more $ to buy an A-lens anymore ^^

[baby007]

The biggest challenge is to set right exposure when the pin is tricked. As I remember, the min/max apertures that the body sees is f/22 - f/1.2 (no matter the real physical lens is.) Using negative EV or a fix amount of speed shift would help, though the amount will vary and depend on the lens.

Here is again more fun. I almost can't express my ideas in English, but I will try my best: I cut off a small aluminum foil from a metal bottle of Tiger beer. This foil will be inserted into the very thin spaces between the lens and the body's mount. The foil doesn't conduct electric as it's painted specially. So if you want to short any pin, you just clean paint at the area associcated to the pin.

The picture will help (Original link: Home / Tag ShortContact | Di?u's FineArt)

# Detect the pin pattern (read this article Features and Operation of the Ka Mount). For example, for f/2 - f/16 you will need to short the pin R2 and the metadata pin

# Locate your contact area on the lens mount and add more spaces


# Create your contact foil


# Put the contact foil between the lens and the body's mount (Actually you can't mount the lens within this foil inserted; just mount the lens normally to the body; after that insert the foil the the ver thin spaces between them.)




Other notes

1. If you need pattern metering, you need to short the meta data pin
2. The M42 lenses are very easy to trick: there is always a enough space for you to insert the foild and you can skip the 2nd step above.
3. Follow my instruction at your own risk!!! As you are going to cause physical changes on your lens mount, and you CAN'T REVERSE YOUR CHANGES. Only do the trick on old / obsolete mount, or M42 lenses
4. Please fix my English and make my posted better and understandable as my English is terribble
5. I successfully create my contact foils that help the body to see the correct min/max aperture for the following lens. (And I can use pattern metering for all of these lenses)
   1. MC Pentacon 1:1.8 50mm (M42)
   2. Super Takumar 1:1.4 50mm (M42)
   3. Rikenon 1:2 50mm (K-mount)
   4. Helios 44m-4 (M42)

I don't like beer much but this time I found beer is really good for lens,at least the way it helps to trick my Pentax K-r And, I don't see the need to pay more $ to buy an A-lens anymore ^^

Very nice trick.
How did you mount the beer foil on the takumar m42 though since the base/flange is not wide enough like M lens?

[hnikesch]

I don't understand tricking a M42 lens as they don't have a aperture lever but use a pin that must be depressed and the Pentax digital cameras can't depress the pin. The only way to close down the aperture is to use the manual setting on the lens so what do you achieve using the "trick"

Hans

[vonBaloney]

I don't understand tricking a M42 lens as they don't have a aperture lever but use a pin that must be depressed and the Pentax digital cameras can't depress the pin. The only way to close down the aperture is to use the manual setting on the lens so what do you achieve using the "trick"

I think what it does is activates full matrix metering on the camera, and you can manually set the aperture on the body, which does nothing on the lens, but gets the info into your EXIF data. And it also allows you to use any shooting mode, right? (Which means you have to mimic aperture on lens with one selected on body.) Unclear on how the exposure works when it thinks you have an 'A' lens and you are stopping down manually with an m42 (letting in less light before the shutter is pressed) -- does it ignore this change of light because it is calculating the exposure instead of metering it directly? Seems like that would screw it up as it would think that whatever light it was getting was "wide-open". Seems like fooling it this way would make more sense with M lenses, but then you've got the aperture-lever problem. (Aperture lever isn't used the same way on M & A.)

[JimJohnson]

No 'A' contact means limited metering and no P-TTL capabilities.

Shorting the 'A' contact and shooting with a stop-down lens like the M42 series, you have to meter wide open, operate exposure lock, then manually stop down the lens to your desired f/stop before taking the picture*. Obviously this is only practical for non-active subjects. On the other hand, 'tricking' your camera does allow you to use some particularly nice old glass on a modern digital camera.

*ideally with the camera told the aperture range of your lens (insulating certain contacts), and doing some tests shots just to make sure no exposure compensation is needed with that lens.

[2000]

Hi everybody, please share pictures of photo series about subject as the link do not work.

Do what JimJohnson said above: Here's a step by step photo series.


I think a piece of thin copper wire pulled from a lamp cord would work well as a substitute for the aluminum foil.

In use, I turn the ewheel f-number as low as it will go and manually preset the lens' aperture. The EXIF is wrong but the exposure is right because the camera doesn't try to close the aperture (I've told it to use the open aperture.)

[icy]

Sorry for any inconvenience. The domain was expired. I will try to allocate the pictures (if any) and I will let you known soon. Thanks.

[JimJohnson]

Back in 2012, I published the message below to a thread about using manual extension tubes with lenses that have a aperture ring and still be able to use the camera's metering. Then I did a follow-on post with pictures. I still use this technique - the comment about it working for only a specific lens is in regard to the extension tube / lens combination. It will work for any lens mounted directly to the camera body.

---

I've been watching this thread. There is an inexpensive solution that doesn't take a lot of mechanical ability or time to implement. The catch is that it works only for a specific lens. As many macro shooters always use the same lens, this shouldn't be a big deal.

There are two steps to use any PK-mount lens with aperture controls (sorry, no DA lens) on manual PK-mount extension tubes as though it was a directly mounted 'A' lens with full in-camera metering. #1- make your camera think that all lens are 'A' lens, and #2- tell your camera what your lens minimum and maximum aperture values are.

It takes five minutes to fool your Pentax dSLR into thinking all mounted lens are 'A' capable. It is totally reversible, but I have yet to have a reason to do so. It doesn't interfere with any of my lens.
https://www.pentaxforums.com/forums/pentax-k-r/178928-kr-short-contacts-chang...ml#post1867401

Next, you have to do some minor alteration to the extension tube that is directly mounted to the camera body. Again, it is reversible if need be. If you are using multiple tubes, you probably only need to do this to your shortest tube, and always mount that one to the camera body first. But it is no big deal one way or the other if you modify all your tubes.
#1- remove any insulating paint from the tube's mounting flange. This will cause all the contacts on the camera body to be shorted (other than the 'A' contact, but you fixed that with the above instructions).
#2- note the minimum and maximum apertures for your lens. Go to this site and use the matrix to determine which contacts should be insulated so they are not shorted.
#3- DON'T use the site's advice to drill shallow divots in your extension tube mount. Sure it works, but the change is permanent.
#4- use very narrow pieces of magic tape to mark which contacts need to be insulated. Place them on the camera body so they are seen outside the mounting flange.
#5- mount the extension tube you prepared in step 1 without insulation on the mounting flange. Now take additional narrow pieces of magic tape and stick them on the side of the tube carefully aligned with the pieces of tape on the camera body.
#6- unmount the extension tube. Place a small piece of magic tape on the mounting flange carefully aligned with the tape on the side of the extension tube. This tape should be no wider than the lens contact point on the body.
#7- remove the tape from the camera body. Carefully remove the tape from the sides of the extension tube. Make sure the tape on the extension tube mounting flange is tightly pressed into place. Trim away any excess tape.

When you mount the extension tube on the body, I suggest pressing in the lens release button before seating and turning the tube. Once the tube is fully seated, release the button and turn the tube backward to make sure it is locked in place. This seems to minimize the chance that you will rip the insulating pieces of tape off the extension tube. Mount the other tubes and/or lens.

You are going to use manual exposure. Set your lens to its maximum aperture. Meter your subject. Lock the exposure on your camera or use manual exposure. Note the aperture shown on your camera body, and set a matching aperture on the camera lens. You don't need to adjust for the light loss caused by the tubes. Your camera will assume it is simply a darker subject. If you do need to adjust exposure it will be for the standard artistic reasons.

make your own auto tube, follow-up
https://www.pentaxforums.com/forums/22-pentax-camera-field-accessories/113756...ml#post1965895

[icy]

Hi everybody, please share pictures of photo series about subject as the link do not work.

I'm very sorry I couldn't find the images. They were deleted from my backup storage for some unknown reason. I also lost all 500 MB images in the archive of this site.