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Forum: Mini-Challenges, Games, and Photo Stories 06-27-2022, 02:59 PM  
Thematic Post Procession Challenge #422
Posted By dms
Replies: 9
Views: 402
I'll play.
Forum: Post Your Photos! 06-25-2022, 02:07 PM  
Landscape Amboy Road, CALIFORNIA. Reworked versions with tamer "blues". What do you think ?
Posted By dms
Replies: 8
Views: 222
Although it may be too much reduction in detail for the foreground, the reworked image perhaps has more of the sense of a distant mountains. And adjusted white balance.
Forum: Post Your Photos! 06-25-2022, 01:48 PM  
Landscape Amboy Road, CALIFORNIA. Reworked versions with tamer "blues". What do you think ?
Posted By dms
Replies: 8
Views: 222
Along w/ what BigMackCam mentioned, if you open the file and pick the white of the clouds to do a color balance, there is a very large shift in the image. (I did in Photoshop CS6 ACR.)
Forum: Post Your Photos! 06-25-2022, 11:02 AM  
Landscape Amboy Road, CALIFORNIA. Reworked versions with tamer "blues". What do you think ?
Posted By dms
Replies: 8
Views: 222
Since you are asking,
-- yes I find the blue a bit too much and the contrast too strong (but that may be me, as I never use PL filter and find Adam's skies are too strong, ...)
-- The other thing is the distant mountain is so clear (sharpened?), I would expect some haze and that would suggest distance.**

_____
** You do mention this and about low humidity. I am more used to film for outdoors, and there I believe the UV light would create the haze. Anyway if you sharpened it you may try not.
Forum: Photographic Technique 06-25-2022, 10:50 AM  
Movies and still photography
Posted By dms
Replies: 16
Views: 967
"I am Cuba" is also one for its photography, including it's creative use of IR film.
Forum: Visitors' Center 06-18-2022, 03:58 PM  
Pentax Binocular Caps
Posted By dms
Replies: 2
Views: 563
Mine (purchased new) did not come with one. Actually a rubber band and some thin plastic/cloth should work fine as the circumference is pretty constant on the objective lens end, after the first 1/4."
Forum: General Photography 06-16-2022, 03:07 PM  
What Lens Do You Use the Most?
Posted By dms
Replies: 68
Views: 3,807
Theater photography 35mm f/2 AF on FF and 16mm f/2.8 FE on APSC
Everyday/in my pocket: Q No. 4 (35mm FF equivalent)
Canoe/Backpacking: 35mm or 35 mm equivalent--in Q, PK, Nikon AI or Nikonos.
Forum: Pentax K-S1 & K-S2 06-15-2022, 09:24 PM  
L bracket for the K-S2?
Posted By dms
Replies: 4
Views: 335
Sunwayfoto DPL-70 is a game changer for light weight cameras. I have it on my KS-2

In my exuberance I did not fully read your question. No this quick release plate (put on end it is an L bracket) does not work for long telephoto lenses. Only works where the center of mass is roughly over/near the bracket
Forum: Digital Processing, Software, and Printing 06-15-2022, 09:12 PM  
THIS is why I don't trust AI image processing software...
Posted By dms
Replies: 50
Views: 2,707
The comments (posts) seem to center on two areas: 1. software is useful but problematic as it/they are altering the images and 2. like anything you need to take care and check it.
These are actually very divergent as there is a difference between (for example) sharpening too much and getting halos and sharpening and getting a sixth toe.

One can know how usual sharpening works and thus what to look for, but one does not know what the software in question does. That is a big difference. For all I know it will replace eyelashes with swastikas, but if I don't check everywhere at the pixel level I cannot be sure!
Forum: Digital Processing, Software, and Printing 06-14-2022, 08:55 PM  
THIS is why I don't trust AI image processing software...
Posted By dms
Replies: 50
Views: 2,707
I use AI sharpen a lot for motion blur mostly (and sometimes for missed focus), in my theatre photography, but nevertheless I have serious misgivings about it (but it is just so good usually). But you need to check what it does, in one case it added a 6th toe (or a finger--I have forgotten now--but I wrote about it in a post here).

I agree to call the software AI is incorrect--while Topaz may have used AI to develop the algorithims in the software, the software does not learn/improve from our using it--so it is not AI.
Forum: General Talk 06-08-2022, 10:12 AM  
Binocular reviews?
Posted By dms
Replies: 21
Views: 815
I also like PAPILIO 6.5x21. It is not waterproof AFAIK, and likely not good in dusk/dawn.
Likely highly subjective, but I find 8x to be too strong and not usable, and for what its worth, my ability to take long exposure hand held is quite good.
Actually I like Fuji GlimpZ 5x21 for canoeing, but also not waterproof.
Forum: Vintage Cameras and Equipment 06-05-2022, 10:35 AM  
Is there a place like "pentax forums" for nikon things?
Posted By dms
Replies: 4
Views: 419
Also would suggest nikongear.net
Forum: Photographic Technique 05-31-2022, 06:25 AM  
Purpose of 81A Filters ?
Posted By dms
Replies: 13
Views: 934
81 A is (as I recall) basically a strong skylight filter. Tungston to daylight requires a stronger filter. Depending if the film was balanced to 3200 or 3400K, it is one of the B or C as I recall.
Forum: Troubleshooting and Beginner Help 05-30-2022, 08:43 AM  
White balance, gray balance, beginners tips
Posted By dms
Replies: 19
Views: 1,105
You can in post set a reasonable WB from the white of the eye, or sometimes any white/gray area in the image. (Gray and white being the same thing, just white has the higher/highest reflectance in the scene.) As noted earlier you don't usually want to reduce the desired effect of sunset, stage lighting, etc. by setting WB to make white/gray look white/gray.

Also with K-5 thru K-1 (no accelerator), the sensor/in camera processing has DR that drops 1 stop for every doubling of iso, after roughly iso 200~400, so instead of - ev you may want to simply leave camera at low iso** and adjust exposure in post--this prevents overexposure and the darks are as good as if one used the higher iso w/o adjusting in post (for me the biggest advantage of using raw). Lots of sites have DR vs exposure for most/all the higher end digital cameras.
_____
** My bad, this only works where you keep the measured exposure at high iso, and then reduce the iso for the shot. For me in theatre photography I don't use light meter, I set low shutter speed and smallish aperture (e.g., 1/30s and f/4), and low iso.
Forum: Pentax SLR Lens Discussion 05-26-2022, 03:12 PM  
New vs Old lenses resolution
Posted By dms
Replies: 56
Views: 4,676
Maybe, although the 50 mm f/1.4 is very low in the corners--probably in part the age of the design, and that it is f/1.4. Aspherical lens design is now common, and I would think the poor rating now would be about 3 times higher resolution.
Forum: Pentax SLR Lens Discussion 05-26-2022, 02:17 PM  
New vs Old lenses resolution
Posted By dms
Replies: 56
Views: 4,676
The top profile is exagerated by not scaling to zero. If they start it at 2/3 of full resolution the top profile will show differences that are three times as large as the ones that start at zero. And if 1/2 of full resolution they will be exagerated twofold.
Forum: Post Your Photos! 05-26-2022, 07:22 AM  
Nature Avocet meeting
Posted By dms
Replies: 4
Views: 172
Very beautiful; however, I think a slight crop to remove the two out-of-focus light spots on the top would strengthen it.
Forum: Pentax SLR Lens Discussion 05-26-2022, 06:55 AM  
New vs Old lenses resolution
Posted By dms
Replies: 56
Views: 4,676
The figures on left may not start at 0 on the y axis. Some test results do this, which means they don't scale similarly to those starting at zero.
In fact they most certainly don't start at zero, as poor does not have 1/5 the resolution of excellent. It should be more like 1/2 to 2/3.
Forum: Pentax SLR Lens Discussion 05-25-2022, 04:39 PM  
New vs Old lenses resolution
Posted By dms
Replies: 56
Views: 4,676
I believe the diffraction limit on resolution = constant * wavelength/f-stop.
It (diffraction limit resolution) is not a function of the lens or sensor--but rather the aperture, but indirectly with lens design and sensor specifics, because a lower resolution lens and/or sensor (larger pixel diameter) does not see the diffraction limit, untill it is no longer lens or sensor limited (e.g., f/22). Thus,

-- a high resolution lens takes the hit at a larger aperture (e.g., f/11) than a lower resolution lens (e.g., f/16).

-- And sensor that has a larger pixel density (e.g., KP vs K-x, or Pentax Q vs K-5) is likely to have the diffraction limit at a larger aperture (e.g., f/5.6 vs f/11).
Forum: Digital Processing, Software, and Printing 05-24-2022, 11:05 AM  
Topaz AI Sharpening
Posted By dms
Replies: 8
Views: 483
I use it for regular sharpening, but it is of my theatre photography so regular means whichever works best (of the 3 choices) and that is usually motion blur.
Forum: Digital Processing, Software, and Printing 05-24-2022, 10:50 AM  
Topaz AI Sharpening
Posted By dms
Replies: 8
Views: 483
If the image is looking good I would not bother. But likely a good approach (what the late Bruce Frazer suggested) is to moderately sharpen the Tif file, and then do final conversion, and change in resolution and sharpen again.

But the real difference that AI sharpen makes is getting rid of motion blur, and to some extent fixing focus. The motion blur aspect is probably what i use it for the most.
Forum: Lens Clubs 05-22-2022, 10:17 PM  
Fisheye Fever Club -- Flaunt your fisheye photos!
Posted By dms
Replies: 3,963
Views: 731,347
I took the liberty of using the 2nd method on your image using PS CS6. I had to fill the lower half in with color (heavy gray lines) as otherwise it would not show up here.
Forum: Lens Clubs 05-22-2022, 09:57 PM  
Fisheye Fever Club -- Flaunt your fisheye photos!
Posted By dms
Replies: 3,963
Views: 731,347
-- In photoshop you can use the edit transform warp to (reasonably) straighten the horizon.
-- Another way would be to enlarge the image veriically so your image is at the top of a much larger (taller) image. Thus the horizon is near the top of the image and then do a lens distortion correction.
Forum: Pentax SLR Lens Discussion 05-21-2022, 07:38 AM  
New vs Old lenses resolution
Posted By dms
Replies: 56
Views: 4,676
Once in the diffraction region every 2 stop smaller aperture (opening) reduces resolution by 1/2, and w/ higher resolution sensor at f/22 you may (as guess-estimates) 1/2 ~ 1/4 the expected resolution, and in macro regime the effective aperture is much smaller, and it depends on the distance, but very possibly you may have 1/4 ~ 1/8 the expected resolution. I suggest you read a book on macro photography that discusses this stuff. The "manual of close up photography" by Lefkowitz (1979) is the best source I have ever read.
Forum: Photographic Technique 05-19-2022, 11:10 AM  
The Double Exposure Faded Technique
Posted By dms
Replies: 6
Views: 828
this reminds one of pre-exposure or post-exposure to cause exposure that is below the threshold for film to become visible, and it does also lead to reduction in contrast (but that is not why you do it and it is a undesirable aspect (you increase DR and thus reduce contrast). One exposes about 3 to 5 stops less than the indicated exposure. (Slide film typically 3 or 4 stops, B&W/color negative 4 or 5 stops.)

With digital I don't think it works as the issue is not a threshold but increasing noise in the shadows, but I am not sure. In any event I gather this is solely about contrast.
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