How to select the appropriate lens hood? - Page 2

georgweb · 11-05-2009, 08:57 AM

Originally Posted by z3r01

Hi G8akjxc8954739 aka georgweb. = ) I got a lil lost when I read your guide on how to check the hood, but I think I get it, it is really informative.

Looking at it i gotta confess I have cut some corners there cause my flickr-space was getting tight.

It is still quite easy:
Put lens + hood on your empty Spotmatic
Open the back. Put in 'B'-mode.
Now, when you push the shutter release and keep it pushed, you can peer from one of the four corners of the film window through the lens and check if the hood is visible. Check it with aperture fully opened first. If you don't see the hood then there should be no vignetting. If you see a small part of the hood you could get away with that hood and very slight vignetting.
If you stop down, the outer portion of the circle will be cut off and that's why vignetting will decrease when stopping down on any lens.

Hope that was a little clearer.
Georg (Spottie-fan)

WheresWaldo · 11-05-2009, 08:33 PM

Here is the copy of HOODCALC.ZIP

HOODCALC.zip

*monochrome* · 11-05-2009, 09:12 PM

Originally Posted by Lowell Goudge

I went back and looked again for the calculations for hood length.

I can no longer find the spreadsheet Hoodcalc.XLS on the web, or the download version Hoodcalc.zip.

It was developed by someone named J.C. Oconnell in 2000,

IIRC John O'Connell was very active on the PDML Mail-List around 2000-2003 and might be reached there. He is also an active seller of Pentax M42 and K lenses on ebay under the UserID jco.

He might respond to an ebay message. jco ebay message link

I have bought several lenses from him over the years.