Vented hoods - slanted or not ??

So, I miraculously found a step-down ring for my Summarit 50/1.5, and now I'll be getting a no-name vented hood (40.5 mm) for it.

Looking at the various options, I find that some vented hoods have straight sides (i.e., parallel to the lens barrel), while some are slanted

inwards. But why exactly ?? I assume that it has to do with making the hood as "invisible" as possible, but would the proper choice

depend on focal length or maybe VF magnification ?? I'm primarily using an M3, but also a IIIa.

 

Thanks :-)

 

Soeren

<p>Leitz introduced the slanted lens hood to reduce viewfinder cut-off as much as possible. The problem is that it only works correctly with the right combination of camera, lens and hood, so that the line of the hood remains at the correct angle to the user's eye-line. On my M3, with a 50mm Summicron and the plastic version of the 12585, which is appreciably thicker than the metal version, the line of the hood is visible but unobtrusive. </p>

<p>Personally, I like the look of the slanted hood, so I also have one on my Olympus 17mm, although even a flared hood wouldn't be visible from the optical finder, in any case.</p>

<p>Soeren, a slanted hood will always be less obtrusive than a straight one, but how much less depends, as H.P. says, on your specific camera. Slanted hoods seem to be made chiefly for 50mm lenses. Largest diameter probably becomes too great when one is made for a wide angle lens. For a long lens, bulk would be increased.</p>

In addition to better visibility (if vented) I think another reason is that even the small amount of reflectivity from light hitting the lower part of the hood will be directed away from instead of up into the lens.

Makes sense - thanks. So a very short lens like the 35/1.4 pre-asph will have a more slanted hood than, say, a 90/2.0.

 

I'll go for a "not-too-extreme" slant and try to remember to post the results here :-)

 

Thanks again !!

<p>As far as minimizing VF obstruction, the slanted hood will work better on an M body, the straight hood on a "Barnack" like your IIIa.</p>