Yes, that is pretty much what I did. The 3M spray puddled on the back of the print - and some got onto the print itself, which went in the bin. For me, using a window mount and double sided tape is a safer option.

Andrew

Yep, I had the same problem with 3M Photo Mount when I tried it -- never again. I'm sure the product is fine - but I don't think I'm quite up to using it effectively.

Andrew

It sounds like a plan to me.

Andrew

Well, my memory was faulty. I might also have been guilty of making an erroneous assumpton about how the tubes are supposed to work mechanically.

Let's hope that Nigel is on the way to a solution.

Andrew

Oh ....... that just might point to the solution. You do need to remove some paint from the tubes so that they short the pins on your camera. You would need to do it on all the tubes. The issue is that if the lens/tubes do not short the pins on the camera, the camera does not know that it has a lens attached, so takes no notice when you press the green button.

You can prove or disprove that notion by cutting a little tinfoil and finding a way to attach it to the correct part of the tube before mounting it on the camera. If you suddenly get stop down metering working, then you know that you have a job to do with some light abrasive paper. Obviously, you would need to take great care to clean the tubes and not get any abrasive anywhere it shouldn't be.

It's a while since I used those tubes and, if they have a painted mount, I couldn't possibly have used stop down metering. Maybe I just guessed or maybe metered on Av (wide open) and calculated the correct shutter speed after setting setting the lens aperture ring.

Andrew

Well, you have a point. The thing I really cannot wrap my head around is that I have used those tubes to take photos with a M75-150 and with a Pentax M 50mm f/1.7 - and I'm pretty sure they worked fine.

David is quite correct, you cannot use stop down metering (or catch-in focus) with a manual lens (or extension tube) that has a painted mount. You have to remove paint from the mount in the same area that the electrical contacts would be in an 'A' lens, until you see shiny metal. I have to do that with a (very good) Chinon 28mm f/2.8 macro lens. Remind me, do the tubes have a shiny metallic mount at both ends?

Andrew

My memory may be faulty, David, but I think those tubes have an unpainted metalic mount. From Nigel's description of what happens mechanically, with a lens/tube combination not mounted to the camera - I can only conclude that they are faulty.

Andrew

I've just checked another set of Jessop tubes with my own M75-150 and that doesn't happen. The lens aperture behaves as you would expect. I have used the tubes that I sent to you with the same M75-150 and they also worked fine - but they've been in a camera bag and not seen daylight for a year or more since then.

A mystery? Yes, I simply cannot explain it.

You have my apologies. It would seem that I have sent you some faulty tubes. Deposit them in the bin and I'll send you some folding drinks vouchers in the post - or alternatively you could send them back to me (I'll refund your postage too)

Andrew

Let's make sure I understand what you are saying here. Are you saying that you can fit your M75-150 to any one of the Jessop tubes (but not to the camera) and, when you look through the tube, the lens aperture is always wide open, irrespective of the setting of the aperture ring??

ANdrew

Nigel, let's try a bit of fault finding .......

Fit your M75-150 zoom onto your K7, set the aperture ring on the lens to f/22. Switch on the K7. Set the exposure mode on your K7 to 'M'. Does the M75-150 stop down when you press the green button (look through the camera viewfinder)?

What happens if you fit one (or any combination) of the Jessop tubes to the M75-150 and press the green button?

Andrew