Rear lens cap: Rodenstock 135mm Sironar-N f5.6

[FredrickSummers]

This should be an easy one, but I have search and got bad results and B&H seems clueless. I bought my Horseman 45HD with a Rodenstock 135mm Sinoar-N but it had not lens caps. I am planning on getting more lenses very soon and would like to put caps on. I purchased a 40.5mm screw on cap just like I had recently purchased for my Hexar 'AF' and really like it. I had found for the rear lens cap to get a 42mm push on, which I purchased from B&H, however it does not fit. Its close, but freely slides on and off (and shipping to return it is the same price as the cap...). Does anyone have a source where I can get a rear cap affordability or know which size I should get? Thank you!

[Bob Salomon]

Just measure the outside diameter with a mm scale and buy that size push on cap.

[Larry Gebhardt]

40.5mm push on is what the Caltar version of that lens uses. I haven't measured the internal threads.

[Steve Goldstein]

Mine takes 40.5mm, which also agrees with the Prograf web page here: http://www.prograf.ru/rodenstock/largeformat_en.html#table1

EDIT: According to my master spreadsheet it's actually 40mm for the rear cap, which disagrees with what Prograf has to say. I'll check it tonight.

[FredrickSummers]

Mine takes 40.5mm, which also agrees with the Prograf web page here: http://www.prograf.ru/rodenstock/largeformat_en.html#table1

For the rear lens cap?

[vinny]

Get some 3M electrical tape. Pull off a few inches and stick it to a smooth surface. Cut it down to about 3/8" wide. Wrap that around the rear element to make the diameter larger than the cap. Peel off and cut until the cap fits snug. Good tape won't leave a residue if removed later down the line.

[Steve Goldstein]

For the rear lens cap?

Sorry, see edit to my earlier post. My spreadsheet says 42mm front cap, 40mm rear cap, and 40.5mm filters. I'll double-check.

[Luis-F-S]

Just measure the outside diameter with a mm scale and buy that size push on cap.

+1

[HMG]

Some time ago, I found this ebay seller with lens caps (http://www.ebay.com/itm/321414227984?_trksid=p2055119.m1438.l2649&var=510289177412&ssPageName=STRK%3AMEBIDX%3AIT) for binoculars and telescopes in hard to find smaller sizes. I haven't purchased any yet and cannot comment on quality.

[FredrickSummers]

Thank you guys, 40mm seems dead on with the rear measurement.


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[Larry Gebhardt]

Cap on mine (Caltar version, but the same lens) is marked 40.5mm.

[FredrickSummers]

Cap on mine (Caltar version, but the same lens) is marked 40.5mm.

For the rear push on? I know the front is 40.5 thread size.