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Forum: Mini-Challenges, Games, and Photo Stories 12 Hours Ago  
Post-Processing PP Challenge #270
Posted By dms
Replies: 19
Views: 677
I made a couple of modifications to my previous version.
(1) The major change is to offer an alternative that is lighter.
(2) A minor adjustment to correct for the apparent barrel distortion of the lens.

I don't know if it is cricket, but the change (lighten the image) was likely the result of seeing some of the other pp versions that were posted.
Forum: Photographic Technique 2 Days Ago  
Exposing for the highlights
Posted By dms
Replies: 21
Views: 731
You mentioned: "Cumbersome because I don't like looking at the screen, a matter of last resort"

But if you want to learn about exposure (e.g., be able to judge how much exposure adjustment to make) looking at the screen after every shot is a godsend--as it gives us instant feedback. Pre-digital we took notes of the shots, and then weeks later saw the developed film, but (except for a Polaroid camera/back) that was the way to get the most complete feedback.

Actually rereading your post, I think you meant you are doing it, but would prefer to see it in the viewfinder. I agree the screen can be problematic, especially so if it is sunny.
Forum: Photographic Technique 3 Days Ago  
Exposing for the highlights
Posted By dms
Replies: 21
Views: 731
1. What CarlJF said. Just set the exposure adjustment for the scene as you plan to take it--using average or matrix metering. If the scene has sky set it to -2ev CORRECTION I meant + 2 e.v., or whatever. if not then no adjustment. Look at results as you do it and after a while you will be good at estimating the e.v. adjustment to the exposure.
2. If metering in M mode w/ green button, and a lens w/ aperture ring, meter as you do now and close CORRECTION I meant open aperture 2 stops after pushing green button, if you have sky to adjust for.
3. If blue sky and you want sky to be correct, just meter the blue sky--away from clouds and away from sun. Again in M mode w/ green button.
Forum: Mini-Challenges, Games, and Photo Stories 09-14-2018, 11:29 PM  
Post-Processing PP Challenge #270
Posted By dms
Replies: 19
Views: 677
Here is my take on it.
Forum: Mini-Challenges, Games, and Photo Stories 09-14-2018, 10:15 PM  
Post-Processing PP Challenge #270
Posted By dms
Replies: 19
Views: 677
When I follow the link it says the owner has not added any files.
Forum: Photographic Technique 09-11-2018, 07:36 PM  
How to set white balance for concert photography?
Posted By dms
Replies: 11
Views: 445


As he says, the off color is likely what is wanted and while rock concerts are quite a bit different than other staged events, I think the following (what I do for theatre productions) is likely true. This assumes shooting in RAW.
-- If the light is way different than the way we see colors if illuminated by tungsten or daylight, then the off colors will be obvious and desirable, thus the lighting intent should be preserved. That may be done by keeping the WB for daylight or tungsten, or anyway something that visually looks like what you saw.
-- If the light is not very different than the way we see colors if illuminated by tungsten or daylight, then you probably want to correct so the people's skin color looks natural, or if mixed lighting, so the major (size-wize)/dominant (emotionally) person looks natural. To do this you can sample/set the WB using a white part of the image--I usually use the white of an eye, a paper napkin, etc.--or simply try changing temperature and tint till it looks correct
-- It's the in-between lighting where you have the problems about what to do. And here it is likely: do you want to satisfy the lighting designers' intentions, the performers desires (if they could tell you), etc., or your own aesthetic?
-- And of course there is always the option (which avoids the issue) of using B&W.
Forum: Non-Pentax Cameras: Canon, Nikon, etc. 09-11-2018, 07:06 PM  
What is it? Mystery item...old Leica lens adapter viewfinder thing...
Posted By dms
Replies: 8
Views: 308
Believe it is the mirror reflex housing that adds an extension to the longer lenses, and turns the RF Leica into a SLR.
Forum: Pentax Film SLR Discussion 08-30-2018, 06:52 PM  
Pentax Analog Spotmeter V calibration
Posted By dms
Replies: 7
Views: 293
Sorry, but having given the above information, I should make a minor correction for completeness.

Dunn's description that I discussed above (on his page 177) does not directly state the reading is from the blue sky--rather it is of a midtone surface reflecting the sun/skylight. Elsewhere he does say the reading of the blue sky under the conditions given above is a check on the meter ("exposure meter middle-tone check level"), except that is on page 165, Table 6.1, where he explicitly says so.

---------- Post added 08-30-18 at 07:02 PM ----------



I don't have/have not used that meter, but it should have an adjustable screw/knob. A quick and effective way (to first do it w/o touching said screw/knob) is to adjust (bias) the iso value. E.g., if the meter yields 1 stop too much exposure, then double the input iso, as compared to the actual iso value. Of course this presupposes the calibration is off by the same amount at all light levels (which is likely the case). Whether this is truly the case is another matter, and comparing to another meter should address this possibility.
Forum: Pentax Film SLR Discussion 08-30-2018, 05:59 PM  
Pentax Analog Spotmeter V calibration
Posted By dms
Replies: 7
Views: 293
On a clear day with the sun fairly high, a reading of the blue sky should be a reliable f/16 at 1/iso sec. With your meter you may have to place it on zone V (a midtone), as opposed to a simpler meter.

---------- Post added 08-30-18 at 06:22 PM ----------

I checked one source (Dunn and Wakefield, Exposure Manual, 3rd edition, page 175-6) where he [Dunn] discusses the calibration of the SEI spot meter which he was the (or one of two) designers for it. He says a reading of the haze-free blue sky with a high sun (above about 45 degrees) is a method for calibrating it. The value will be 10,000 lumens per sq. ft. which he says corresponds to 1/125 sec at f/8 with ASA (ISO) 25 film. This would be the same as 1/125 sec at f/16 at iso 100--which is very close to the 1/100 sec, using my prescription above. I have seen others recommend metering the blue sky and 1/iso at f/16 (e.g., 1/100 sec at iso 100) for this calibration, but don't recall now where.
Forum: Pentax SLR Lens Discussion 08-30-2018, 12:03 PM  
Replace DA 15 and Rokinon 8mm with DA 10-17?
Posted By dms
Replies: 12
Views: 298
Comparing a fish eye lens in conjunction with Fisheye-Hemi software to a rectilinear lens, I now prefer a fisheye for times I want a very wide FOV. Specifically:

1) the fish eye lens plus Fisheye-Hemi results are actually more realistic (here I am using a FF fisheye lens on a cropped sensor dslr)

2) the fisheye is much wider FOV than the same FL in a normal lens

3) unless using a FF fisheye on a cropped sensor lens, and even then, I find I almost always need to use fisheye hemi--so there are more steps in the pp--and you need to use software that accepts fisheye hemi (e.g., photoshop)

If you look in the PF reviews of software you can see an example where I compare fisheye lens (the Q #3) w/ and w/o fisheye-hemi. I find about 1/3 of the theatre photographs I take (and give to the producer) are taken with the Pentax 16 mm f/2.8 (FF) fisheye on a cropped sensor K-5.
Forum: Pentax SLR Lens Discussion 08-25-2018, 05:36 PM  
What do all the graduations and markings mean on lenses?
Posted By dms
Replies: 17
Views: 687
Hyperfocal distance (H) specifically refers to the distance at which half the distance set (the hyperfocal distance) to infinity will be in focus, while for other distances the markings show depth of field.

If interested it turns out the inverse of the set distance, and the near and far distances, are related by the average of their inverse's. E.g., if H=6 ft, then (1/3 + 1/infinity)/2 = 1/6.
Forum: Digital Processing, Software, and Printing 08-10-2018, 10:10 AM  
Printing at home - what's the real cost?
Posted By dms
Replies: 18
Views: 1,114
I think the question about printing at home is not the cost so much, because you can decide to only print small and use a good dye ink printer. Rather it is (or was/is for me):

(1) The ability to work on the image till it is really satisfying. How the tweaks in pp and the choices in paper will change things cannot really be done otherwise, and (for me) it is probably 50% of the making of the image--which is very different and more satisfying from what I did in the film era.

(2) In fact if you plan to give out the work, for example for 13"x19" and larger, printing at home gives one the ability to investigate the choices (1) with smaller prints, and then maybe print a slice of the larger print to proof the larger prints you go out for. As I mentioned when I wanted larger prints (2 ' x 3' prints from my college print department) I used this method--although as it turned out the results were basically identical--but from what I read that is likely not the case when going out to a larger volume commercial printer.
Forum: Digital Processing, Software, and Printing 08-09-2018, 09:01 AM  
Printing at home - what's the real cost?
Posted By dms
Replies: 18
Views: 1,114
I use epson w/ dye not pigment (6 set Clara) and:
-- I have no trouble w/ clogging so far (10 years use, often a month or two between printing)
-- color fastness is fine (does 100 vs 200 years matter?)
-- appearance is as good as high end pigment inks for matte--where I use it for tests to compare to larger print results where I want bigger prints. I have heard the glossy results are even better for dye vs pigment, but I have not done any A to B comparison.

The Epson 1430 will do 13x19 and it allows user input for any size paper up to the 13 " by something quite long (maybe 144"). I don't have the 1430--I have a 10 year old all in one, that only accepts 8.5" wide), but the inks are the same.

BTW accumulate a few images to print and then print narrow slices of each on the same paper as test to get the image right for the final print. I don't use calibrated screen and anyway the print works by reflected light, versus the transmitted light for the screen, so some trial and error is often called for IMO (including deciding what paper to use).
Forum: Troubleshooting and Beginner Help 08-08-2018, 07:28 PM  
what could cause this kind of halo-ish stripe in the sky? K-1 II
Posted By dms
Replies: 23
Views: 816
You mention it was raw file. Presumably you processed it 16 bit and adobe RGB or ProPhoto RGB, because initially I thought the banding could be from pp in 8 bit and sRGB as color space.
Forum: Pentax DSLR Discussion 08-07-2018, 07:01 PM  
Focus Screen Compatability
Posted By dms
Replies: 11
Views: 473
I found spot metering to be usable if the aperture (for the metering) was at (about) f/2.8 as I recall. I had made up a table of e.v. corrections versus aperture, but in the end I stopped using it (my e.v. corrections) and did w/o spot metering--but it did work except it slowed things down--and other ways of doing things worked better for me.
Forum: Photographic Technique 08-07-2018, 06:28 PM  
Action K3 Settings for Kuaui Helicopter Photography
Posted By dms
Replies: 7
Views: 373
Although not iso invarient I believe the K-3 is close to it--so likely better to stay at a low iso, and fixed aperture and fixed shutter speed. Assuming you are flying during the day I would think iso 100 and 1/4000 at f/2.8, or 1/2000 at f/4 (basically starting slightly less exposure than w/ sunny f/16 rule). That should be fine for anything from overcast to full sun.

If you are flying at night it is a different story--then I think the shutter speed will need to be quite low--hopefully SR will make a big difference, and the resulting night lights need not be very sharp. From my experience with film photography from commercial airplanes I would suggest/guess a fast prime lens wide open (f/1.4 to 1.8), and high iso (as it is the lights and not the dark areas that are important), and moderate shutter speed. Maybe f/1.8, iso 1600, and 1/60s (this because w/ iso 320 slide film I usually used f/1.8 at 1/15 s).

Another consideration is are you doing pp in camera raw? My recommendation is based on using raw, as I have no experience pushing the exposure with jpg's.

BTW the lens wide open is f/2.8 no matter what the sensor size is. This equivalence thing is confusing and often (I believe) about depth of field--which is not a consideration here.
Forum: General Photography 08-06-2018, 05:35 PM  
How often, sensor cleaning?
Posted By dms
Replies: 32
Views: 819
Moderate usage of/changing lenses for a decade and never cleaned the sensor. Regularly used the Giotto rocket blower. Unless there is (visual) dust/artifacts on the sensor that cannot be removed by the air jet, cannot see a reason for cleaning, and on the other hand the possibility of damaging the sensor suggests one should not physically touch it for no strong reason.
Forum: Pentax K-1 07-01-2018, 06:13 PM  
Rokinon 8mm lens with K-1
Posted By dms
Replies: 10
Views: 885
If you want a full circle for the image** (while not the most elegant solution):
-- you can crop to a circle in pp
-- or possibly (?) mount a circular cutout in front of the lens (that vignettes to a circle).***
-- Also it may be some pp software allows you to do a mathematical mapping from the actual image to a circle (one would likely expect if anyone does it, it would be photoshop, but I did not investigate further/try it) .
_____
** Finding a lens that shows the image as a circle does not ensure that the actual FOV will be as large as what you get from this 8 mm FE.

*** You probably would do better mounting a circular cutout to the rear of the lens. The rear of this lens is reasonably flat and the rear most glass does not protrude. With photo tape it should be pretty easy, just need to experiment with the diameter of the hole.

Also you could look for a older lens attachment that converts the FOV to a circle--Spiratone for example. This will do it, and will be inexpensive, but the image quality will suffer. Older Pentax Takumars apparently have a 24mmx36mm rectangle image. Older Nikon's had it--especially for atmosphere/sky photos for cloud cover studies--and they may be usable on K mount, but it may require the mirror be manually raised, and in any event they are likely very rare and costly.

Thinking more about it--I should have realized my Pentax fisheye the SMC-A 16 mm f/2.8 (or the earlier K 17 mm f/4) had a gel holder on the rear of the lens, so you could make a circular cutout and in complete safety mount it on the lens. The 17 mm f/4 also was available as a Takumar--but I don't recall if it had a gel holder (BTW there is currently one [or was anyway] listed at KEH).
Forum: Pentax SLR Lens Discussion 07-01-2018, 02:57 PM  
Pentax lenses that are worthy of an A* or Limited designation but are not
Posted By dms
Replies: 49
Views: 2,126
SMC-A 16mm f/2.8 fisheye. Superb mechanically and optically.
Forum: Photographic Technique 06-27-2018, 07:47 PM  
Raynox on a reversed lens?
Posted By dms
Replies: 24
Views: 824
They are both magnifying lenses, but the reversed lens is likely much greater in magnification, and if they are comparable in magnification the reversed lens having more glass elements should be the better-- but a reversed lens works on shorter FL, while the simpler diopter (Raynox) can work on longer FL (where it gives higher magnification) and thus gives more working distance from the object being photographed. They work best under different conditions.

BTW you can try a simpler single lens diopter to see how well it suits you. (A cheap set, +1, +3, +5 for example--likely $10 as a guess.) And then if you like it get the Raynox (which I assume is a 2 lens diopter), or equivalent ones made by Nikon/Canon/Etc, but you will know better what power you want.

---------- Post added 06-27-18 at 08:06 PM ----------

If you want to know what is possible, and the advantages/results using differing approaches, I would suggest you get a used copy of "The Manual of Close-Up Photography," by Lester Lefkowitz, Amphoto, 1979.
Forum: Post Your Photos! 06-26-2018, 09:16 PM  
Misc Happy National Canoe Day!
Posted By dms
Replies: 7
Views: 212
I agree--it would be a shame to not use canvas on it, as it was so originally, and with a place to store and work on it. Ideal is probably an aluminum or composite one for very tough trips, although watching Bill Mason's films, he took a canvas and wood canoe everywhere.
Forum: Troubleshooting and Beginner Help 06-21-2018, 12:23 PM  
Pentax M 50mm f1.7
Posted By dms
Replies: 9
Views: 621
And you must be in M exposure mode for K mount lenses w/o an A setting (i.e., pre A/F/FA, etc. lenses)
Forum: Pentax SLR Lens Discussion 06-16-2018, 10:21 AM  
Pentax M 20mm F4 - hood suggestion
Posted By dms
Replies: 22
Views: 816
Not for FF, but efficient (and not very deep) on APSC is the Takumar (metal rectangular) 28 mm f/3.5 hood. I put some photo tape along the side however, so I don't unknowingly bump it/push it askew.
Forum: Pentax K-1 06-14-2018, 09:56 AM  
Rokinon 8mm lens with K-1
Posted By dms
Replies: 10
Views: 885
Christopher Frost did a review on FF and cropped Cannon, in 2016. It shows the image on both--you get quite a bit more on FF. Correction it was 2014. (Sorry I don't seem to know how to copy the link.)
Forum: Pentax SLR Lens Discussion 06-13-2018, 08:36 PM  
35mm Takumar...Meh Colors
Posted By dms
Replies: 19
Views: 881
Some of the non-smc (35mm f/3.5) are in fact smc. Pentax did not identify them initially as smc.

And for the OP, I also suggest a hood. I use the square metal 28 and 35 mm takumar hoods (49 mm filter size) on a lot of my 24 to 35 mm FL lenses on cropped sensor.
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