Lens element swap?

[jolefler]

Hi folks...new to computers (first post), please bear with me. I use an old 13.5cm Tessar on my 4x5. The front element has a good sized nick in the glass which I blacked-out. I haven't been able to pick up any negative affects under a loupe, but don't enlarge prints to any great size. Recently I purchased a front element, in good shape, for the same glass (except barrel mounted). As I understand it, front and rear elements are matched....should I bother having the front elements swapped by a photo-machinist, or would the results possibly be worse than what I have now. Since the shutter and barrel threads differ, it's not just a screw out/in procedure...I'm somewhat sure both front elements would have to be dis-assembled to pull off the swap. Opinions, please.

[Dave Parker]

If your not showing any negative artifacts in your pictures, I would not worry about it, a nick normally if bad can change contrast or flare possibilities in images, the front element can actually take quite a bit of abuse before showing much, I would think the cost would be quite high as everything would have to be placed right and calibrated to ensure alignment. Like I said, if your not showing any artifacts in your images, I would not worry about it.

Dave

[avandesande]

Photo machining is very expensive and really only worth it for rare protar sets and 19" Dagors. There are others too but I know tessars aren't one of them.
If you are handy with tools and can get a spanner wrench it wouldn't hurt taking them apart and switching elements. If it takes lousy pictures you know the elements arent matched very well.

I would tell you not to bother with any of this but nobody ever seems to take this kind of advice.

[Ole]

If it needs machining to swap the elements, it will probably be more expensive to get it swapped (and the spacing correct) than to get a new old lens. Or two.

If it gives no negative effects, I would keep on using it. One of my favorite lenses has a deep scratch in the rear element, it still takes great pictures.

[jolefler]

I believe I'll leave well enough alone, based on the advise. Perhaps if I fall in love with another of my focal lengths I'll try it myself. Doh!