View Full Version : Why won't a 86mm filter will not screw into my Rodenstock Sironar-N?
AtlantaTerry
21-Oct-2013, 16:01
I bought an 86mm filter for my 300mm f5.6 Rodenstock Sironar-N lens but it only screws in about 1/2 of a turn then stops.
The lens threads are pristine, there are no dings, dents or bends. So what is going on? :confused:
Did Rodenstock use some sort of non-standard threading on the lens? If so how do I get filters, step rings, etc. to properly work?
Thanks.
Terry
Two guesses, you bought a wrong filter size or it's a chinese no name brand filter, similar story is I bought some step rings off the Bay for cheap
and ... welll, they were cheap, a few of the step ring's were either badly threaded, or they were overzealous with the anodizing. Had the same
issue you have, they threaded on 1 or 2 turns then stopped.
Using those as a key ring now.
Jim, it sounds like what your problem may have been is thread pitch. I know all of the cheap step-rings are 0.75mm thread pitch, while many older filters/lenses are 0.5mm thread pitch. Also problematic is that larger lenses sometimes have 1mm thread pitch.
I use some step rings on older lenses and they only screw in about one half turn, but I just use them that way with no problems.
Terry, since you've got a larger 86mm filter, it may be 1mm, I don't know. If so, you'll probably need to make sure the filter you buy is also 1mm pitch.
Corran, it was not a thread pitch issue, it was a set of 8 step rings and I was screwing them into each other.
Lachlan 717
21-Oct-2013, 20:14
It can also be mixing metals.
Often, the rings are aluminium, whilst the threads are often brass. Different expansion rates caused differences in thread/groove.
I have had this happen with metal lens caps. Good design in principle; PITA in practice!!
pasiasty
22-Oct-2013, 03:58
86mm filter threads are either fine (M86x0.75) or coarse (M86x1.0); the latter pitch is more common, and your Sironar should have it (see catalogue (http://www.cameraeccentric.com/html/info/rodenstock_3.html)).
Buy a cheap step-up ring on eBay, e.g. 86-95, and try if it screws in. And another with internal thread 86 (e.g. 77-86) and try if the filter screws in. The cheap, Chinese rings are available only with common pitches. Or use a (metric) pitch gauge.
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