Extension tubes/faulty camera

Hi
Whenever I used extension tubes with my MZ7 or MZ5n and a Tamron macro lens I lost aperture data in the viewfinder, I seem to recal reading somewhere that this was due to reducing the effective maximum aperture of the lens, however when I recently tried this with my istD (yes its taken me two years to try it for macro work) I still lose the aperture info in the viewfinder and LCD but it is still recorded in the EXIF data, this got me to thinking that if the camera "knows" which aperture the lens is set at because of the info in the EXIF then why cant it display it in the viewfinder and LCD is this some strange annonally or is my camera faulty?

Hi I.S.,

I'm guessing that you have PKA extension tubes (with the electrical contacts), as opposed to PK ones that have no contacts, just the aperture lever thing, otherwise there's no way the camera would know the aperture for the EXIF data. So I'm also guessing that the camera would need one particular contact to read the aperture for display, and presumably setting it from the body, but perhaps a different one would give info back to the camera??

I've noticed that some lenses have more contacts than others, but I don't know what these contacts do. However, I can guarantee someone here does, so I'm sure you'll get a proper answer in due course.

I can't imagine it's a fault with the camera, if it was the same with the MZ's. The only difference now is that you can see the aperture in the EXIF data, so you know there's some sort of communication going on.

But why did it take you so long to try macro with your D???

All the best,
Dan

Hi
thanks for the input.
your right about the various contacts on the bodies/lenses sometime they dont even seem to match up.
The reason it took so long to try the tubes on my istD was a combination of several things, but primarilly after getting settled in a new house this was the first summer that I have had the chance to spend anytime in the garden, I tried a combination of KA tubes along with a cheap (Centon) ringflash, The beauty of digital at least is that I can check the exposure of the flash while making sure I have enough DOF, take a dozen shots and into the house to upload. I was so pleased with the results I visited a public garden to see just what species of plant we needed to introduce to attract the various little beasties! My familly think I'm mad wanting to attract more bees and wasps into the garden, actually they think I'm totally off my rocker anyway cos' I have this tendancy to try and stroke bumblebees.

My Great Great Aunt's Daughter-in-Law used to stroke Bees all the time. They would quite happily sit on her hands and endure this, or maybe they liked it, and they never once stung her.

Personally, I am not going to try it.

Yeah, there are some odd sorts about!

Anyway, good plants for attracting bees, hoverflies, butterflies and moths include:

Buddleia
Verbena bonariensis (I think that's how you spell it )
Fennel (we have a bronze fennel, absolutely smothered in hoverflies and wasps at the moment, but does self-seed very readily, need to keep it in check)
Sunflower
Foxglove


There are plenty of books around which will tell you the best plants to have - Chris Baines wrote the definitive wildlife gardening book, but there are many others, including several in association with the ublications:books" rel="nofollow" class="outlink" target="blank">Royal Society of Wildlife Trusts.

Cheers,
Dan

Spider, does everything display when you're using just the lens?

Don't know if it is affected but how up-to-date is the istD firmware - I think they're up to V1.2

Firmware version for the istD is 1.12, unless I've missed something

http://www.pentaximaging.com/customer_care/show_firmware?firmId=1

Another thing to check is the AD2 adaptor on your Tamron lens, if it's this type - i.e. a manual focus lens with removable adaptor. It needs to be a PKA mount too, but I guess perhaps you would already know that.

And you should have the lens aperture ring set to 'A'. If not, the value won't show on the body (but then it shouldn't be recorded in the EXIF data either , well certainly isn't on my D).

Found this which explains what the different contacts are used for.

Dan

Yes I get full display without extension tubes.

Not sure about the firmware (have updated it once)

It is a KAF mount so no adaptor, there is an "A" setting/lock on the lens.

If you hold down the 'menu' button whilst you turn the camera on, it will tell you what version you have loaded. Not sure though that the firmware version would make any difference, from the description of the updates given on the pentax website.

If you want to send me your PKA tubes, I'll try them out for you. I'll send you my PK ones to be getting on with, until I'm finished with yours. Not sure how long that would be...

Dan

OK guys

BIG apologies, I got it sussed.

First off, a slight error in my first post, I re-checked my MZ7 and 5n, I didn't lose info on the 5n (its that long since I used it, but I was sure I lost it on that as well, must be getting senile).

It was actually the weblink from Daniel that got me on the right track, I got all my lenses out in front of me and compared the contacts then compared the contacts on the extension tubes. then I noticed an extra contact on the FAJ lens and a distinct shortage of contacts on my tamron macro.

My money is on the fact that the contacts on the KAF lenses can be used to convey different data to different camera bodies, the older bodies like my MZ5n are programed to read the lens contacts in one way whereas the later model bodies read the data differently. Although I might just be talking a load of bull.

I put this to the test, I tried every lens I have (not the FAJ) on my MZ5n, every lens gave me aperture info in the viewfinder when used with extension tubes, my 28-80 my 80-320 and my 28-200 sigma, and the tamron.
I tried this with my MZ7 and the istD, nothing.

Bottom line is when using an "A" series lens on the MZ5n you have to use the aperture ring in manual mode to change the aperture setting, I also tried the MZ5n in total TV and Manual modes the aperture info was still displayed, I think its safe to assume that modern cameras do read the lens contacts in different ways and that my extension tubes are just throwing a spanner in the works, probably all tied in with the multi-segment metering and this maximum aperture lark (read Daniels link) .

And my firmware is V1.12

Sorry Daniel looks like my tubes will be staying in Yorkshire, but I am definately going to have to do a set of controled exposures to see if I am getting correct metering.

I had the same problem with my istDS/18-55mm DA and a set of PKA tubes (Jessops I think). You may find that the end of the tube that the lens attaches to is chromed but the body mount end is painted (read insulated). In my case, the camera and lens had more contacts than the tubes. The remedy I chose (cheaper than a new set of tubes) was to carefully scrape away some of the paint on the body mount end of each tube to reveal the aluminium underneath. They work perfectly now, even when using more than one.

Hope that helps.

Peter, you are a star!

Mine are also jessops tubes, and with a little bit of paint off they work just fine, so I suppose part of my theory was correct, the different bodies have a different way of communicating with the lens, the tubes worked fine on my MZ5n cos the data was routed through different contacts.

Right no stopping me now, its macro only for the next two months!

You are welcome. I'm happy to know that the three days I spent figuring out my tube problem has eventually helped somebody else

I hope to see some of your work here very soon . . . .

Cheers,