My solution to the 40mm Summicrion lens hood problem

<p>The Problem:<br>

The collapsible rubber lens hood that comes with the 40mm Summicron eventually weakens and rips free from the aluminum ring that screws it into the lens AND acts as a retainer for the series 5.5 filters that the Summicron uses.</p>

<p>For me, the rubber came off the lens hood about the same time as my original Leitz UV series 5.5 filter wore out and needed replacing. So, two problems actually - inneffective hood shading and hard to find 5.5 filters.</p>

<p>My Solution:<br>

Because a regular 39mm filter has a slightly different thread pitch than the 39mm hood's thread, you can screw in a 39mm filter thread about one full turn until it snugs up tightly but without damage to any threads. Then the rubberless hood screws into the 39mm filter, again finger tight. This forms a long hood ahead of the lens, but introduces vignetting in the corners. Filing out the corners of the hood ring to match the 3:2 rectangle, you can get rid of the vignetting and then have a hood with a nice tight light-shielding capability. I just blacken the filed/sandpapered aluminum with a few coats of a permanent marker.</p>

<p>Another nice benefit is that the original snap-on lens cap, which is one of the great cap designs of all time, still fits snugly and pops off as easily as before.</p><div></div>

<p>Another view of the lens hood...</p><div></div>

<p>And a side viewing showing hood depth...</p><div></div>

<p>Nice solution! It is interesting that Leitz (-Minolta) used a different 39mm screw pitch than on their other lenses with 39mm screw threads. It is perhaps nothing new to you (as a large format user) or some others, but vignetting is easy to observe with any attachments by looking through the camera body from the back with the shutter open, while tilting the body to see if the lens attachments come into view or not (one can also do the same from the front while observing whether the film plane edges appear or not).</p>

<p>I didn't have a hood or cap to start with, but I found that a macro ring to old Zenit (that has same thread as LTM, 39x1mm) can be screwed almost all the way into Summicron's filter ring. Then I had 40,5x0,5 mm thread cut into the other end, so now I can use my russian filters with it. I do regret not cutting the outside diameter down so i could use those russian lens caps without mounting a filter or an empty filter ring first...</p><div></div>

<p>These look like useful adaptations for the missing rubber lens hood. Luckily for me, I have a good lens hood and a new old stock back-up lens hood.</p>

<p>Or... you could just buy a metal screw on 39mm lens hood from heavystar...<br>

<a href="http://www.google.com/products?q=heavystar+lens+hood+39mm&hl=en&aq=f">http://www.google.com/products?q=heavystar+lens+hood+39mm&hl=en&aq=f</a></p>

<p>Your suggestion, Harrison, is where I was leaning, until a friend suggested that I do the file trick. He had seen the hood I made from a generic metal lens hood for my 45mm Pentax 67 lens by cutting and filing it into a petal shape that perfectly matched the corners of the super-wide lens, and suggested I do the same. The ability to retain the snap cap was what sealed the deal.</p>