Hood or no hood (image style)

stevebrot · 07-28-2014, 11:19 PM

Originally posted by Steve.Ledger

Hoods generally give better contrast.

Yep, and the lower contrast without is due to veiling flare.

Steve

---------- Post added 07-28-14 at 11:26 PM ----------

Originally posted by JimmyDranox

A long lens like a 70-200mm, with a lot of glass and diaphragms inside, even if we don't see it easily, has good anti flare properties already.

It is sort of the other way around and heavily dependent on the quality of the internal coatings. Internal reflections from the glass surfaces are the primary cause of veiling flare and are multiplied in lenses having a large number of elements. Internal baffles, if well-designed and adequately flocked can reduce reflection from the inside of the lens barrel, but back-scattering from adjacent glass surfaces are still present.

Steve

JimmyDranox · 07-29-2014, 01:41 AM

Originally posted by stevebrot

Yep, and the lower contrast without is due to veiling flare.

Steve

---------- Post added 07-28-14 at 11:26 PM ----------

It is sort of the other way around and heavily dependent on the quality of the internal coatings. Internal reflections from the glass surfaces are the primary cause of veiling flare and are multiplied in lenses having a large number of elements. Internal baffles, if well-designed and adequately flocked can reduce reflection from the inside of the lens barrel, but back-scattering from adjacent glass surfaces are still present.

Steve

Yes, back-scattering from glass are present, but they're present with or without hood. I've seen it many times, when I took pictures of Moon or Jupiter with 70-200mm/2.8, and even with good Apo refractors telescopes.

**dms** · 08-08-2014, 01:03 PM

I did a quick and dirty test of Tiffen ultra contrast filter (#3). The result is:

-- the filter results in no change to highlights and a lowered contrast w/o a gain in detail.

With a slow (contrasty) film I would expect the filter to yield more detail--but I have no prior experience w/ this kind of filter.

(The details are)

With a high contrast scene I metered the sky and increased exposure to put sky at maximum acceptable level. The results (a crop and a 100% crop of the darkest area, first w/o the filter and then w/ the filter) are provided.**

First two photos--NO FILTER, k-x at iso 100, w/ takumar 28mm f/3.5 w/ hood at f/16, ACR curve=linear

Second two photos--WITH THE FILTER, k-5 at iso 100, w/ VS1 28mm f/1.9 w/ hood at f/16, ACR curve=medium contrast

In photoshop I made minor exposure adjust (-0.35 and 0.30 as I recall). The curve setting of linear is my usual setting for such a scene (and then in photoshop I usually do a midtone sharpening for contrast--but I did not do this here).
_______
** Actually the contrast difference is evident on my Mac in photoshop, but much less so on viewing in this post. Not sure why.

Zafar Iqbal · 08-08-2014, 02:54 PM

Thanks for posting the samples, dms

I like what you got from the photo using a filter. Of cause I do not know how the contrast difference looked before posting to web, but I think it's different enough. Many times, especially during dinner (low light/high iso) black suits can become too dark and lifting those up just the slightest, will be a huge benefit - or so I imagine.

**dms** · 08-08-2014, 07:17 PM

Yes, the filter does lighten (all) the darker areas. I likely will try a few more comparisons--except with the same camera--so the only difference is the presence/absence of the filter, and post it here.

**dms** · 08-09-2014, 05:21 PM

I thought more results w/ and w/o the filter would be interesting--so I started a thread (www.pentaxforums.com/forums/22-pentax-camera-field-accessories/269951-tiffen-ultra-contrast-filters-results.html#post2902713). I included some later results I obtained (more carefully done--w/ the only significant variable being the filter itself).

Zafar Iqbal · 08-10-2014, 05:59 PM

Originally posted by dms

I thought more results w/ and w/o the filter would be interesting--so I started a thread (www.pentaxforums.com/forums/22-pentax-camera-field-accessories/269951-tiffen-ultra-contrast-filters-results.html#post2902713). I included some later results I obtained (more carefully done--w/ the only significant variable being the filter itself).

Great. Thanks for the link!

08-09-2014, 05:21 PM	#21
dms Site Supporter Join Date: Aug 2011 Location: New York, NY Photos: Gallery Posts: 2,192	Started Thread on Tiffen Ultra Contrast Filter Results I thought more results w/ and w/o the filter would be interesting--so I started a thread (www.pentaxforums.com/forums/22-pentax-camera-field-accessories/269951-tiffen-ultra-contrast-filters-results.html#post2902713). I included some later results I obtained (more carefully done--w/ the only significant variable being the filter itself).

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07-28-2014, 11:19 PM	#16
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Steve.Ledger Hoods generally give better contrast. Yep, and the lower contrast without is due to veiling flare. Steve ---------- Post added 07-28-14 at 11:26 PM ---------- Originally posted by JimmyDranox A long lens like a 70-200mm, with a lot of glass and diaphragms inside, even if we don't see it easily, has good anti flare properties already. It is sort of the other way around and heavily dependent on the quality of the internal coatings. Internal reflections from the glass surfaces are the primary cause of veiling flare and are multiplied in lenses having a large number of elements. Internal baffles, if well-designed and adequately flocked can reduce reflection from the inside of the lens barrel, but back-scattering from adjacent glass surfaces are still present. Steve

07-29-2014, 01:41 AM	#17
JimmyDranox Veteran Member Join Date: Oct 2012 Location: Ploiesti, Romania Photos: Gallery \| Albums Posts: 1,632	Originally posted by stevebrot Yep, and the lower contrast without is due to veiling flare. Steve ---------- Post added 07-28-14 at 11:26 PM ---------- It is sort of the other way around and heavily dependent on the quality of the internal coatings. Internal reflections from the glass surfaces are the primary cause of veiling flare and are multiplied in lenses having a large number of elements. Internal baffles, if well-designed and adequately flocked can reduce reflection from the inside of the lens barrel, but back-scattering from adjacent glass surfaces are still present. Steve Yes, back-scattering from glass are present, but they're present with or without hood. I've seen it many times, when I took pictures of Moon or Jupiter with 70-200mm/2.8, and even with good Apo refractors telescopes.

08-08-2014, 02:54 PM	#19
Zafar Iqbal Veteran Member Join Date: Oct 2010 Photos: Gallery Posts: 1,229 Original Poster	Thanks for posting the samples, dms I like what you got from the photo using a filter. Of cause I do not know how the contrast difference looked before posting to web, but I think it's different enough. Many times, especially during dinner (low light/high iso) black suits can become too dark and lifting those up just the slightest, will be a huge benefit - or so I imagine.

08-08-2014, 07:17 PM	#20
dms Site Supporter Join Date: Aug 2011 Location: New York, NY Photos: Gallery Posts: 2,192	Yes, the filter does lighten (all) the darker areas. I likely will try a few more comparisons--except with the same camera--so the only difference is the presence/absence of the filter, and post it here.

08-10-2014, 05:59 PM	#22
Zafar Iqbal Veteran Member Join Date: Oct 2010 Photos: Gallery Posts: 1,229 Original Poster	Originally posted by dms I thought more results w/ and w/o the filter would be interesting--so I started a thread (www.pentaxforums.com/forums/22-pentax-camera-field-accessories/269951-tiffen-ultra-contrast-filters-results.html#post2902713). I included some later results I obtained (more carefully done--w/ the only significant variable being the filter itself). Great. Thanks for the link!