I've a pentax ME super with an 'm' 50/1.7. My Pentax ME Super is a very pretty little camera and nice and light but it doesn't have dof preview. For composing my people photos I find 'fulltime' dof preview on my Canon AL-1 + FL lens combo invaluable. Really I should call it oof preview as I'm not actually too bothered about dof.

So I was thinking that rather than tfind an m42 lens to get want I want (with likely inferiour coatings and so no good for backlit shots of which I am quite keen) maybe I could snip something off the pentax-m 50/1.7 to give me fulltime oof preview.

Anyone know if this is possible and how to do it?

Basically you want to convert the lens to be preset aperture. This involves removing the stop-down lever and also removing the aperture follower. The former so the lens is always at working aperture, the latter so it doesn't confuse the camera's metering system.

Thanks, Mawz.

Is this as simple as snipping them off or should I be taking the lens apart?

[I won't have the lens in front of me till I return to France later this month, so I'm rather guessing: perhaps it would be obvious that snipping isn't possible with the thing in front of me]

lorriman wrote:
Thanks, Mawz.

Is this as simple as snipping them off or should I be taking the lens apart?

[I won't have the lens in front of me till I return to France later this month, so I'm rather guessing: perhaps it would be obvious that snipping isn't possible with the thing in front of me]

You can snip the stop-down lever, but will need to disassemble the lens to get the aperture follower.

Thanks, Mawz, for your help to a newbie to the world of fiddling with lenses.

Do you think it's worth the effort? I don't have any significant tools apart from a pair of pliers though I;m not unwilling to buy some equipment especially with future lenses in mind though I have no idea what to get.

The choice is to risk wrecking a lens or just buy myself an m42 equivalent. Is the risk really significant? I really would like to have the advantage of that smc coating and I like the bokeh on this lens.

I actually do like doing a bit of DIY but need to get a handle on what would be sensible.

It's a great leans with no M42 equivalent. It's also common enough that replacing it is no real issue.

I'd go ahead and modify it, you should only need a set of screwdrivers (ideally JIS, but you can get away with standard jewellers screwdrivers) and a pair of tinsnips.

Ok, thanks for the encouragement. I'm set on doing it.

I've been looking around to get myself the mentioned equipment but I'm pretty clueless. I'm looking at this list of tinsnips: I'm looking to spend as little as possible of course but would rather not falsley economize. What you recommend against the £7 snips?

What sizes of JIS screwdrivers should I be looking for?

Yeah, cheap tinsnips are fine. I'm not 100% sure how JIS screwdrivers are sized, but you'd want the equivalent of #0 and #00 Phillips sizes.