Okay, I know that many things I should look at when checking a used buy have certainly been mentioned here or there, anywhere, but I can't find a whole thread on it. Sure, scratches, S/N and/or issue date as of age, and colour, inclusion of hood, covers, etc is clear. What about all that pocket light (torch) beaming, fog, yellow droplets etc etc? Today I'm into the "current" Elmarit-M 2.8/90 (Article No. 11807, and I know that means an S/N of 3462071 or higher). Thanks for all of your tips and tricks!

Mike

-- Michael Kastner (kastner@zedat.fu-berlin.de), July 09, 2001

Answers

1. Shine penlight from front and rear, looking at about 45-degree angle from opposite end. Play light around. You're checking for fungus (looks like a spot with fuzzy "aura" around it, or worse, like spiderwebs or frost patterns on a window. Also, you're checking for scratches. I use a magnifier like a jeweler wears...ok, maybe I'm a bit obsessed.

2. Make sure aperture is smooth, not too loose or tight, and no oil on the blades from either side. On SLR lenses check auto diaphragm for crisp snap-back, then mount it and check that DOF preview stops it all the way down. Then fire it at slow shutter speed at each aperture looking from the front, to see that it stops down consistently. Check finder display at various apertures to make sure the meter coupling is properly cammed.

3. Check focus. Should stop dead on infinity, no tight spots during rotation. With M lenses, check that it couples properly to the rangefinder. Sight on a sharp target 1-2 miles away at infinity as well as 5m and 1m.

4. Check for dents. A few bright marks are nothing, but a dent means it could have been dropped which isn't healthy.

5. Check the screws and spanner slots for evidence of disassembly, including look with magnifiers for signs of goring and burring that have been painted over with flat-black. A competent repair facility would never leave signs of disassembly...if you can see any, it's a sign that someone untrained might have had it apart.

-- Jay (infinitydt@aol.com), July 09, 2001.

Hi Jay,

Thanks for everything. Yup, in the meantime I had of course discovered your news in the earlier, amazingly-entitled posting "90mm lens questions" (http://www.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=005gmP) regarding the 45° lighting etc. I can't think of anything you haven't broadcasted which I really need that much, except maybe the possibility/trial/experiment of checking out a roll overnight first. Only problem here is that for a good plunge and a great price (which is here NOW) the seller just might not feel like it (the overnight roll).

Thanks again and best regards, Jay. Mike

-- Michael Kastner (kastner@zedat.fu-berlin.de), July 09, 2001.

To check lens(new or old ) you need two loupes, a 4x loupe and a 20x loupe.

I always bring my Octoscop to check out camera or lenses

I would turn my Octoscop into cross position, so that I can conveniently switch between 2x, 4x, 10x and 18x loupes

To check out lenses for any fungus, dust, debris in the internal lens elements, turn the lens to maximum aperture, point the lens to sky or a bright ceailing, but not directly against the light source, use 2x or 4x loupe on the Octoscop, move toward and away fron the lens, focus on different layer lens surfaces of lens elements, check for any small dust ( look white ) or debris (black) or fungus( star like); it is not enough to check lens with naked eyes. 10x or 20x loupe has too short focus to perform dust/debric/fugus check.

Then use 18x loupe of Octoscop to check for the screws to check for sign of tempering.

-- martin tai (martin.tai@capcanada.com), July 11, 2001.

1. Shine penlight from front and rear, looking at about 45-degree angle from opposite end. Play light around. You're checking for fungus (looks like a spot with fuzzy "aura" around it, or worse, like spiderwebs or frost patterns on a window. Also, you're checking for scratches. I use a magnifier like a jeweler wears...ok, maybe I'm a bit obsessed.

Whilst I agree with Jay in essentials. Looking at even a new lens will no doubt show you all sorts of dust particles and some crud in the lens this way. A good example of this is the dust in a brand new projection lens which you can see clearly once the bulb in the projector is illuminated. My point is that you should not be too paranoid about dust found inside the lens. Fungus or significant scratches, I agree, you need to notice, but you can get obsessive about all this - most of the time it makes no difference to the final image as these particles and so on are nowhere near being imaged on the focal plane.

-- Robin Smith (smith_robin@hotmail.com), July 20, 2001.