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01-20-2009, 09:36 AM   #1
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About Lens Hoods RETAKE!

There were a few people that suggested that the differences could be due to bad focus, inconsistent focus...

I went back, did the same test with a tripod and a remote... the biggest difference was that the lighting wasn't as harsh... the difference in
the photos is there in terms of contrast however it doesn't appear to be as big a difference as in the first test. however i would like you all
to keep an open mind that in the real world more contrast can equal better AF, i initially focused with the hood on for that reason, also in
the real world focus isn't always accurate between 2 photos.

Here is the testing arena taken with the Pentax 10-17mm fish-eye to show the lighting



Here are the 50mm tests (no hood on the left, new hood on the right)

@ F1.4


@ F2.0


and @ F2.8


you may draw your own conclusions but i can see an improvement with the hood.

01-20-2009, 10:57 AM   #2
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Why are you shooting against a high contrast background of the window.

If you want to see how the lens hood reduces stray side light, the windows should be to the side of the lens, not shining light right into the lens.
01-20-2009, 11:51 AM   #3
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QuoteOriginally posted by alohadave Quote
Why are you shooting against a high contrast background of the window.

If you want to see how the lens hood reduces stray side light, the windows should be to the side of the lens, not shining light right into the lens.
I was thinking the same thing, shouldn't the light source be off the the side (out of the field of view but still able to hit the front element when no hood is present)? Obviously even with the light where it was there was some improvement from the hood, but I think it would be more marked with side light.
01-20-2009, 01:56 PM   #4
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Hmm. With these, I don't see a difference.

01-20-2009, 02:50 PM   #5
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QuoteOriginally posted by alohadave Quote
Why are you shooting against a high contrast background of the window.

If you want to see how the lens hood reduces stray side light, the windows should be to the side of the lens, not shining light right into the lens.
QuoteOriginally posted by heliphoto Quote
I was thinking the same thing, shouldn't the light source be off the the side (out of the field of view but still able to hit the front element when no hood is present)? Obviously even with the light where it was there was some improvement from the hood, but I think it would be more marked with side light.
Ok... yes there is back-lighting... it was deliberate but there is also side lighting... there are 2 windows yes 2 windows one behind the subject and one off to the side of the subject out of the frame... i guess that fish-eye 10mm 180 degree FOV shot wasn't good enough to demonstrate this... i would do another test because some people don't seem to be able to be satisfied... but its just a little to dark out and i don't want to use artificial light for this experiment... you'll just have to wait till sometime tomorrow
01-20-2009, 02:52 PM   #6
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QuoteOriginally posted by scole Quote
Hmm. With these, I don't see a difference.
Look for contrast... how well defined the shadows and light areas are... look at the text, its clearer on one then the other
01-20-2009, 03:58 PM   #7
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I'm curious, would you happen to have the Pentax stock hood for this FA lens? I'm wondering how much of a difference it would make in these same conditions.

01-20-2009, 04:06 PM   #8
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QuoteOriginally posted by smigol Quote
I'm curious, would you happen to have the Pentax stock hood for this FA lens? I'm wondering how much of a difference it would make in these same conditions.
no i don't... my best guess is that a larger hood on an FA lens and a crop body would do better then an FA hood on an FA lens on an FF body
01-20-2009, 09:51 PM   #9
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Hi Smigol, I have the same lens (FA 50/1.4), bought new, and it did not come with any lens hood nor is there any way to mount one, other than to use some type of screw-in type that goes inside the threads. (Boo!) This is in contrast to the very nicely designed hood for the sister (or brother ) lens, the FA 35/2, which can also be stowed backwards on the lens when not in use. I'd like to pick up some kind of hood for the 50 myself...

Anyway, nice work Mike, definitely a worthwhile effort, much appreciated and you've given us all some food for thought. Thanks!
01-20-2009, 10:15 PM   #10
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QuoteOriginally posted by MightyMike Quote
Ok... yes there is back-lighting... it was deliberate but there is also side lighting... there are 2 windows yes 2 windows one behind the subject and one off to the side of the subject out of the frame... i guess that fish-eye 10mm 180 degree FOV shot wasn't good enough to demonstrate this... i would do another test because some people don't seem to be able to be satisfied... but its just a little to dark out and i don't want to use artificial light for this experiment... you'll just have to wait till sometime tomorrow
Well, I'm satisfied, and I thank you for your posts - incredibly informative! However, I do think that the majority of the outside light is coming from behind the subject, based on the FE shot, you can see the shadow of the table legs cast toward the camera's position. I know that the hood won't be able to block out that light, so I think you'd be able to demonstrate the effect of the hood even more impressively with one window behind you and one maybe at your 10 o'clock or so. You're just lucky that light comes into your house through your windows... I have windows, but they are all either shaded by trees or big roof overhangs, and if I want light I have to burn electrons to get it.

Keep up the good experiments!
01-20-2009, 11:38 PM   #11
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The hood I'm thinking of is the one that I purchased as an accessory:

Here's the link to the B&H page:
Pentax | 49mm Rectangular Lens Hood | 34021 | B&H Photo Video

I see on the Pentax store that they sell a different hood now:
PentaxWebstore 49mm Lens Hood PH-RBC

The square one that I got has a nice pinch-type grip, allowing pretty easy application. Not sure how the newer, round style attaches other than screwing on the threads.

I'll try my own tests and see how it does.



QuoteOriginally posted by NeverSatisfied Quote
Hi Smigol, I have the same lens (FA 50/1.4), bought new, and it did not come with any lens hood nor is there any way to mount one, other than to use some type of screw-in type that goes inside the threads. (Boo!) This is in contrast to the very nicely designed hood for the sister (or brother ) lens, the FA 35/2, which can also be stowed backwards on the lens when not in use. I'd like to pick up some kind of hood for the 50 myself...

Anyway, nice work Mike, definitely a worthwhile effort, much appreciated and you've given us all some food for thought. Thanks!
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