Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
10-29-2018, 06:46 AM   #1
New Member




Join Date: Oct 2018
Posts: 5
Which Hood

Hi fellas first post but a long time lurker so be gentle...... Lol

I am after a hood specifically for my Pentax SMC M 28mm f3.5, can someone point me in the right direction as there appears to be a couple of different rectangle hoods for the different models of lenses.

10-29-2018, 07:12 AM   #2
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 28,172
QuoteOriginally posted by Vmlopes Quote
Hi fellas first post but a long time lurker so be gentle...... Lol

I am after a hood specifically for my Pentax SMC M 28mm f3.5, can someone point me in the right direction as there appears to be a couple of different rectangle hoods for the different models of lenses.
What format? Film 35mm, APSC digital, k-1?
10-29-2018, 11:21 AM   #3
Site Supporter
Site Supporter
jlstrawman's Avatar

Join Date: Feb 2010
Location: Midwest US
Photos: Gallery
Posts: 1,058
https://www.pentaxforums.com/lensreviews/SMC-Pentax-M-28mm-F3.5-Lens.html

Last edited by BigMackCam; 10-29-2018 at 12:59 PM. Reason: Fixed link
10-29-2018, 12:55 PM   #4
New Member




Join Date: Oct 2018
Posts: 5
Original Poster
QuoteOriginally posted by UncleVanya Quote
What format? Film 35mm, APSC digital, k-1?
Sorry should have mentioned its APSC

10-29-2018, 12:58 PM   #5
New Member




Join Date: Oct 2018
Posts: 5
Original Poster
That link is dead
10-29-2018, 12:59 PM   #6
Digitiser of Film
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 20,574
QuoteOriginally posted by Vmlopes Quote
That link is dead
I've fixed the link. It should work now
10-29-2018, 01:04 PM - 1 Like   #7
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 28,172
SMC Pentax-M 28mm F3.5 Reviews - M Prime Lenses - Pentax Lens Reviews & Lens Database

Hood listed is PH-S49 (28/35) as opposed to the more common PH-S49 (50) which is also available and is deeper. The 50mm version is also avaialble from JJC and others - it my be possible to get the JJC and hacksaw it down to a thinner overall size but it will be pretty ugly.

Pentax PH-S49 (28mm/35mm) aka PH-SB49 Rectangular Plastic Hood reviews - Pentax Camera Accessory Review Database

---------- Post added 10-29-18 at 04:05 PM ----------

QuoteOriginally posted by BigMackCam Quote
I've fixed the link. It should work now
Beat me to it!

10-30-2018, 04:12 AM   #8
Pentaxian
deus ursus's Avatar

Join Date: Nov 2012
Location: Stårheim, Norway
Posts: 657
QuoteOriginally posted by UncleVanya Quote
Hood listed is PH-S49 (28/35) as opposed to the more common PH-S49 (50) which is also available and is deeper.
For APS-C the latter might work anyway?
10-30-2018, 04:15 AM   #9
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 28,172
QuoteOriginally posted by deus ursus Quote
For APS-C the latter might work anyway?
I agree it might. I know it works on the DA 35 f 2.4, I have personally tried that.
10-30-2018, 04:04 PM   #10
Pentaxian
deus ursus's Avatar

Join Date: Nov 2012
Location: Stårheim, Norway
Posts: 657
I briefly tested the hood from my DA 40 on an M 50/1.4. I couldn't see any vignetting on the test shot, but I didn't check on all apertures.
10-30-2018, 07:05 PM   #11
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 28,172
QuoteOriginally posted by deus ursus Quote
I briefly tested the hood from my DA 40 on an M 50/1.4. I couldn't see any vignetting on the test shot, but I didn't check on all apertures.
The opening of that hood is roughly 30.5mm which in rough theory means a max f stop of 50/30.5 = f/1.63 which would be hard to eyeball vs no vignetting. Realistically the aperture could be larger or smaller than that due to the optical effect on the effective pupil size.
10-31-2018, 10:21 AM   #12
Loyal Site Supporter
Loyal Site Supporter
rogerstg's Avatar

Join Date: Oct 2007
Location: Rhode Island
Photos: Albums
Posts: 1,168
QuoteOriginally posted by UncleVanya Quote
The opening of that hood is roughly 30.5mm which in rough theory means a max f stop of 50/30.5 = f/1.63 which would be hard to eyeball vs no vignetting. Realistically the aperture could be larger or smaller than that due to the optical effect on the effective pupil size.
Wouldn't you need to add the length of the hood to the 50mm original focal length in the aperture equation?
10-31-2018, 10:30 AM   #13
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 28,172
QuoteOriginally posted by rogerstg Quote
Wouldn't you need to add the length of the hood to the 50mm original focal length in the aperture equation?
I don't think so. You haven't changed focal length you have simply restricted the opening. the opening being farther forward might make it look smaller than it is slightly but the real optical question is how large does the effective pupil become which I am unqualified to answer with anything more than this rudimentary guess. I know that the hood in question doesn't have a lot of length either so that may be fairly moot in terms of impact.
10-31-2018, 11:21 AM   #14
Loyal Site Supporter
Loyal Site Supporter
rogerstg's Avatar

Join Date: Oct 2007
Location: Rhode Island
Photos: Albums
Posts: 1,168
QuoteOriginally posted by UncleVanya Quote
You haven't changed focal length you have simply restricted the opening
But isn't it like the focal length changed with respect to FOV? My simple minded way of thinking about this is that if the length of the hood increases, at some point it will cause vignetting, despite the opening remaining the same. FOV decreases as length increases.

I should probably stick to my day job, which obviously has nothing to do with optics, though these interesting conversations help me to better understand the factors affecting photography.
10-31-2018, 11:45 AM   #15
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 28,172
QuoteOriginally posted by rogerstg Quote
But isn't it like the focal length changed with respect to FOV? My simple minded way of thinking about this is that if the length of the hood increases, at some point it will cause vignetting, despite the opening remaining the same. FOV decreases as length increases.

I should probably stick to my day job, which obviously has nothing to do with optics, though these interesting conversations help me to better understand the factors affecting photography.
It will. But that's a function of angle of view vs. hood diameter and length. It doesn't alter the focal length of the lens. So a 50mm with a long cardboard tube from a paper towel roll will vignette but it remains a 50mm.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
hood, jjc, k-mount, lens, pentax, pentax lens, pentax lens reviews, pentax-m 28mm f3.5, reviews, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
DA* 50-135mm lens hood replacement - would a Canon hood fit!? kp0c Pentax SLR Lens Discussion 6 02-05-2015 07:28 PM
k 135mm 2.5 hood - can i use the tak hood? The dog walker Pentax SLR Lens Discussion 7 12-18-2013 11:11 AM
Difference between Pentax '67ii' folding focus hood and '67' folding focus hood? rustyair Pentax Medium Format 3 10-02-2013 08:10 AM
Hood or no hood? woonona_butch Troubleshooting and Beginner Help 23 11-11-2010 06:30 AM



All times are GMT -7. The time now is 03:02 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top