Appropriate hood for my Kaleinar 3B 150/2.8

deadwolfbones · 12-01-2009, 09:05 AM

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Hi guys,

I'm looking for an 82mm metal screw-in hood for my Kaleinar 3B, which is a 150mm f/2.8 Pentacon-Six medium format lens. It has a ridiculously huge, probably uncoated front element, and it definitely needs some glare protection.

On eBay I see two different 82mm "tele" hoods. One is pretty long, and one is a bit shorter. The long one says it's for 200mm lenses and up, but since the equiv. focal length on the Kaleinar is 225mm, I'm not sure if it's the one to go with or not.

Can anyone tell me if "effective focal length" is a consideration when choosing the right hood, or whether I should just go with the shorter one?

Thanks!

**Lowell Goudge** · 12-01-2009, 10:33 AM

there used to be a spreadsheet application on the internet called HoodCalc.xls that could give you an exact calculation of the maximum hood length, based upon the physical properties of the hood (ID specifically) and the diameter of the front element of the lens the focal length and the sensor dimensions.

I do not know if it is still accessible, but it is worthwhile.

try this lnk
http://translate.google.ca/translate?hl=en&sl=ko&u=http://www.pentaxclub.co.....zip%26hl%3Den

deadwolfbones · 12-01-2009, 11:15 AM

Originally posted by Lowell Goudge

there used to be a spreadsheet application on the internet called HoodCalc.xls that could give you an exact calculation of the maximum hood length, based upon the physical properties of the hood (ID specifically) and the diameter of the front element of the lens the focal length and the sensor dimensions.

I do not know if it is still accessible, but it is worthwhile.

try this lnk
Google Translate

Blocked by my work firewall, unfortunately, but I'll check it when I get home. Thanks!

**Lowell Goudge** · 12-01-2009, 11:29 AM

Originally posted by deadwolfbones

Blocked by my work firewall, unfortunately, but I'll check it when I get home. Thanks!

it should be downloadable, and it might make a good thing tu upload on the accessories forum, with a sticky, if you can.

A couple of words of warning.

The front element diameter is NOT the filter diameter, but the actual diameter of the glass.

Also, when calculating length, you need to consider that the front element is recessed in the lens body somewhat. you need to subtract this from the final length, otherwise you could get vignetting.

Valdormar · 05-08-2013, 01:10 PM

I have used both the tele & standard 82mm thread mount lens hoods with out any issue.

D1N0 · 07-31-2020, 05:09 AM

On aps-c or full frame a longer hood would work as well since vignetting would be way of the sensor. I found my 67mm Takumar 200/3.5 hood (67mm) fits well with a couple of step down rings. This should still be ok when adapted to any modern digital MF sensor.

12-01-2009, 09:05 AM	#1
deadwolfbones Veteran Member Join Date: Sep 2007 Location: La Crescenta, CA Posts: 7,450	Appropriate hood for my Kaleinar 3B 150/2.8 Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here. Hi guys, I'm looking for an 82mm metal screw-in hood for my Kaleinar 3B, which is a 150mm f/2.8 Pentacon-Six medium format lens. It has a ridiculously huge, probably uncoated front element, and it definitely needs some glare protection. On eBay I see two different 82mm "tele" hoods. One is pretty long, and one is a bit shorter. The long one says it's for 200mm lenses and up, but since the equiv. focal length on the Kaleinar is 225mm, I'm not sure if it's the one to go with or not. Can anyone tell me if "effective focal length" is a consideration when choosing the right hood, or whether I should just go with the shorter one? Thanks!

12-01-2009, 10:33 AM	#2
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,886	there used to be a spreadsheet application on the internet called HoodCalc.xls that could give you an exact calculation of the maximum hood length, based upon the physical properties of the hood (ID specifically) and the diameter of the front element of the lens the focal length and the sensor dimensions. I do not know if it is still accessible, but it is worthwhile. try this lnk http://translate.google.ca/translate?hl=en&sl=ko&u=http://www.pentaxclub.co.....zip%26hl%3Den Last edited by Lowell Goudge; 12-01-2009 at 10:43 AM.

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12-01-2009, 11:15 AM	#3
deadwolfbones Veteran Member Join Date: Sep 2007 Location: La Crescenta, CA Posts: 7,450 Original Poster	Originally posted by Lowell Goudge there used to be a spreadsheet application on the internet called HoodCalc.xls that could give you an exact calculation of the maximum hood length, based upon the physical properties of the hood (ID specifically) and the diameter of the front element of the lens the focal length and the sensor dimensions. I do not know if it is still accessible, but it is worthwhile. try this lnk Google Translate Blocked by my work firewall, unfortunately, but I'll check it when I get home. Thanks!

12-01-2009, 11:29 AM	#4
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,886	Originally posted by deadwolfbones Blocked by my work firewall, unfortunately, but I'll check it when I get home. Thanks! it should be downloadable, and it might make a good thing tu upload on the accessories forum, with a sticky, if you can. A couple of words of warning. The front element diameter is NOT the filter diameter, but the actual diameter of the glass. Also, when calculating length, you need to consider that the front element is recessed in the lens body somewhat. you need to subtract this from the final length, otherwise you could get vignetting.

05-08-2013, 01:10 PM	#5
Valdormar Inactive Account Join Date: Mar 2011 Photos: Albums Posts: 3	I have used both the tele & standard 82mm thread mount lens hoods with out any issue.

07-31-2020, 05:09 AM	#6
D1N0 Pentaxian Join Date: May 2012 Location: --- Photos: Gallery Posts: 6,802	On aps-c or full frame a longer hood would work as well since vignetting would be way of the sensor. I found my 67mm Takumar 200/3.5 hood (67mm) fits well with a couple of step down rings. This should still be ok when adapted to any modern digital MF sensor.

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