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Forum: Digital Processing, Software, and Printing
09-21-2016, 11:51 AM
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The 8-bit limitation for Elements is the number one reason why I don't use that tool. The big question is, why does that bother me? Below is a mix of computer fact and conventional wisdom mixed with personal experience:- Bit depth (how many data bits per color per pixel) determines both the number of and the values for the colors in your image
- With 8-bit color, that provide 16.8 million colors (256 shades for each of red, green, and blue). The 256 figure is the important one.
- Increasing the depth to 16 provides about 65,536 shades for red, green, and blue for a total of 281 trillion colors. Way overkill, right? Yes, your eyes cannot fully differentiate the millions of the 8-bit palette, much less 281 trillion! Again, the 65,536 figure is the important number.
- Most people's eyes can easily differentiate most of the 256 shades of, say, true blue and therein lies the problem with 8-bit color (see fifth point on the next list)
The list above is very basic and there is actually more to it at the data and hardware level. Now how about a few practical considerations?- JPEG images are limited to 8-bit and lower
- TIFF supports multiple bit depths, but 16-bit is most common
- PNG supports either 8-bit or 16-bit color
- RAW capture with a Pentax camera will either by 14-bit or 12-bit, depending on the camera
- With 8-bit color, issues like banding of blue skies and/or sunsets are much more common. In short, subtle color gradations are more difficult to render.
- While all adjustments in PP have the potential to generate artifact, the tendency to do so is much higher in an 8-bit working environment
- Despite nominal support for 16-bit color, Photoshop Elements is, for all practical purposes, an 8-bit working environment and for most purposes and for most people that works fine. The processor and memory requirements are lower allowing for snappy response and fits well with the JPEG images that most people shoot.
- I won't go into the full list of reasons (very involved), but staying with 8-bit JPEG has many advantages in terms of hardware requirements, file size, and image consistency between displays/media.
- Photoshop, Lightroom, PaintShop Pro*, and several other tools provide a 16-bit work environment
- Working at a higher bit depth allows for more robust editing (less artifact and better tone gradation) and more flexibility for print and screen output
- You can work with 8-bit images in a 16-bit work environment, but the limitations (less data) of the image may affect the scope of what may be done without artifact
- All of the above totally ignores the important considerations of display limitations, color gamut, and color space. For a detailed explanation of color in digital photography, I have found the tutorials at the Cambridge in Color Web site helpful:
Tutorials on Color Management & Printing
Conventional wisdom for serious work goes like this:- Capture at high bit-depth and wide gamut (what we did not talk about above). Usually this requires RAW capture.
- Edit at high bit-depth and wide gamut
- Publish to the bit-depth and gamut of the target media. For the Web that generally means 8-bit JPEG in the sRGB color space (also not talked about above).
- Note that the publication step may create unexpected shifts in color and contrast that the photographer should be aware of and should account for
I hope this helps.
Steve
* Many of PSP's features are 8-bit only. Its inclusion with the other tools is based on its color management capabilities in general.
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Forum: Pentax SLR Lens Discussion
04-09-2016, 12:39 PM
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I have 6 ways to get to 200mm
Of the lenses I tested, five images taken, best of 5, the DA*s performed well, both in terms of best image and highest number of keepers. In number of keepers, the Sigma 18-250 didn't produce a very good image, and it's other 4 were much worse. That makes evaluation really easy, unlike the DA*s where more than one images could have been selected as the best . Nothing else was close.
I could do a lot more, like calibrate each lens, blah, blah, blah, but basically, I don't have time to calibrate a lens every time I take it out.
All images taken on a tripod with a 2 second delay.
The results on this one are pretty clear cut, no surprises. The only two lenses I thought performed reasonably well were the DA*s. And I'm pretty sure that was because the distance which was probably about 120 feet was long enough to obscure some of the detail. Which would mean all lenses were less than equal the task, if you wanted to read all the small print, making the differences between them stand out more. There is no additional PP after the Apple import presets for the K-3, not even the levels slider bars were adjusted.
Based on my lenses, shooting at ƒ5.6 I liked the DA*60-250 best, but the DA*200 was right there with it, close enough further testing could reverse the order.
Next was the Sigma 70-300 and F-70-210. In last place the Sigma 18-250, with an old Vivitar 135 with the 1.7 TC on it bringing up the rear.
I would have done this as a poll, but to me the results were too obvious to bother. The only real question being DA*60-250 or DA*200, and those ar close enough, there would need to be more testing.
The focus point was on the ladder, so the centre circle on the focus screen was touching both sides of the ladder, with the top of the ladder even with the top of the circle.
Group one, sharpest.
DA*60-250
DA* 200 Notice that the A*200 is clearly sharper on the lettering on the inside of the ladder. Interesting.
Group 2
F-70-210
Sigma 70-300
Group 3
Sigma 18-250
Viitar M135 ƒ2.8 with F 1.7 AF adapter.
Despite clear differences in the Pixel peepers, reduced to 1200x800 they are pretty close.
Pixel peeping.
Group one, guessed sharpest.
DA*60-250
Too close to call DA* 200
Group 2, not very close
F-70-210
Sigma 70-300
Group 3, do they actually call these lenses?
Sigma 18-250
Viitar M135 ƒ2.8 with F 1.7 AF adapter.
Pixel peeping on the edge
Group one, guessed sharpest.
DA*60-250
DA* 200_ oops, camera must have moved.
Group 2, not very close
F-70-210
Sigma 70-300
Group 3, do they actually call these lenses?
Sigma 18-250
Viitar M135 ƒ2.8 with F 1.7 AF adapter.
Nothing unexpected here, the worst modern zoom was the one with the highest zoom ratio, the DA*60-250 and DA* 200 were pretty close.
* it should be added after using them both in low light the DA*200 has a clear AF advantage.
** the Sigma 18-250 just got back from Sigma after an AF repair, and calibration, and a requested test for de-centering, which as per the invoice, wasn't done. Sigma may take your lens back under warranty. Whether or not they can make it a good lens is another question.
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Forum: Pentax SLR Lens Discussion
03-13-2016, 01:25 PM
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Forum: Pentax SLR Lens Discussion
03-12-2016, 10:11 AM
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FA* 28-70
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Forum: Pentax SLR Lens Discussion
03-11-2016, 01:03 PM
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Forum: Weekly Photo Challenges
03-09-2016, 10:48 AM
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Forum: General Photography
02-23-2016, 04:08 PM
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Sometimes it works to you advantage.
A few years back, I called to inquire about a CL ad selling "a box of camera equipment."
- What are there in the box?
- A bunch of stuffs: cameras, lenses, and other things I don't know.
- How many cameras are there?
- Two.
- Can you tell me the wordings on the cameras?
- Yeah....see.... one says... pentax.... s... f... one, the other.... says.... Pentax... i... i... x.
- How about lenses? How many are there?
- Oh.... four.... oh no.... five.... yes, five of them.
- Can you tell me the wordings on the lenses?
- Uhm..... pentax... a.... one colon... one dot four... eight five mm...uhm....
- OK. How much do you want for it?
....
At the end, I paid $400 for, among other things, a Pentax LX body, a Pentax-A* 1:1.4 85mm, a Pentax-A* 1:4 300mm, and a Pentax 1.7X AF adapter.
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Forum: General Photography
02-23-2016, 01:57 PM
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I have a SMC Pentax-M 75-150mm lens for sale on the local Craig's List.
Message: Do you still have the lens?
Me: Yes, I do.
Message: Is it a good lens?
Me: Yes, it is a very nice, clean lens, as the photos in the ad indicate.
Message: Is it sharp?
Me: Yes, it is very sharp.
Message: Does it take sharp pictures of people?
Me: Yes.
Message: Does it take sharp pictures of landscapes?
Me: Yes, it takes sharp pictures of whatever you're photographing.
Message: Will it fit a Canon C camera?
Me: No, as is says in the as, it is a Pentax "K" mount lens.
Message: What does that mean?
.......... I give up. No more replies. It just ain't worth my time and trouble for a $50 lens.
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Forum: Pentax K-1 & K-1 II
02-23-2016, 06:19 PM
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There are probably at least 300 if you include the M42 stuff. The key is that the 36 Mpx sensor is only a little more of a challenge then the 14.6 Mpx sensor in the K-7. The main difference is that deficiencies in the edges/corners visible at that pixel pitch will be exposed. Painful as it may be to admit, those issues exist in new lenses too. Despite the assertions of some reports here and on the Web, most lenses designed for 24x36mm do not have a performance cliff at 14.4mm diameter from center of frame rendering them acceptable for APS-C only. Here are the talking points:- Any drop in performance towards the corners will be similar to that visible on a film image from the same lens*
- The better lenses made prior to the so-called digital era are generally good for optical enlargements** up to 24"x36" assuming superb technique and high resolution film
- Those same lenses should be capable of at least that large a print from the K-1's 36 Mpx sensor assuming the same superb technique
- Superb technique = careful attention to focus + minimization of camera motion + minimization of subject motion + suitable subject (not all subjects lend themselves to large prints) + high quality print technique
Based on my experience with the lenses on my shelf, I have high expectations for the following:- Pentax-FA 35/2
- Super/S-M-C/SMC Takumar 55/1.8
- Pentax-K 55/1.8
- Pentax-M/A 50/1.7
- Pentax-FA 77/1.8 Limited
On the "B" list, meaning that they will probably be fine and may actually surprise me. All work well on the K-3 and film:- KMZ MC Zenitar 16/2.8 Fisheye
- Tamron 28/2.5 (02B)
- Vivitar 28/2.8 (Komine, K02)
On the "special case" list, meaning that the lens is not superb, but I get nice images anyway. All work well on both the K-3 and film, but on film they are "different" and "good" in the non-traditional sense:- LZOS MC Jupiter-9 85/2
- KMZ Helios 44M 58/2
- Auto-Rikenon 50/1.8
Of the above lenses, the Helios is distinctly soft in the corners on 24x36 format, but still useful. The J-9 may be a little soft for some taste, but appropriate for some subjects. Bokeh on the J-9 is to die for and the Rikenon is "dreamy" wide open.
Ooops! :o You only asked for three, but you have probably figured out that the list above represents the lenses that have consistently delivered for me on both formats.
Steve
* For normal display as hung art, the eye (brain) tends to discount faults present at any distance from the center of visual interest and it is unusual to have elements of visual interest at the edges/corners. Translation? Some very nice images were made on 35mm film and deficiencies in edge performance were not a significant source of frustration for those shooting on that format.
** Paradoxically, a well-made optical enlargement from a negative will generally outperform a digital scan + ink-jet print from the same. Though, as always, there may be exceptions to that rule.
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Forum: Lens Clubs
02-13-2016, 11:35 AM
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this afternoon
ISO 80 - 360mm - f5.6 - 1/400s
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Forum: Post Your Photos!
02-13-2016, 01:02 PM
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Forum: Troubleshooting and Beginner Help
02-14-2016, 04:12 AM
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So, if you'd like to max out Portrait + Bokeh, you can do it as much as you like with the DA*50-135. You can make more bokeh by your setup rather than the lens. Basically, the distance between your camera and the subject must be less then the hyperfocal distance and the greater the distance between your subject and the background, the more bokeh you'll get. If you use a 50mm lens even a fast one, you'll not have a lot of bokeh, but if you use a longer focal length such as your 50-135 @135mm, you'll get more bokeh than with the 50mm f1.8 because: 50/1.8 < 135/2.8 .
Below is a list of lenses to select from based of bokeh potential:
Pentax FA31 f1.8: 31/1.8 = 17
Pentax DA35 f2.8: 35/2.8 = 12.5
Pentax DA40 f2.8: 40/2.8 = 14.3
Pentax DAL50 f1.8 : 50/1.8 = 28
Pentax DA*55 f1.4 SDM: 55/1.4 = 39
Pentax HD70 f2.4 Ltd: 70/2.4 = 30
Pentax FA 77 f1.8 Ltd: 77/1.8 = 43
Sigma 85 f1.4 HSM: 85/1.4 = 61
Pentax DFA100 f2.8 Macro: 100/2.8 = 36
Pentax DA*50-135 SDM @ 135mm: 135/2.8 = 48
Pentax DA*200 f2.8 SDM: 200/2.8 = 71
Pentax DA*300 f4 SMD: 300/4 = 75
The higher the number, the more bokeh potential, but be aware of the angle of view that's needed to frame your subject. Even if the DA*300 is capable of completely blurred background, its angle of view is very narrow, difficult to use especially for large subjects. The Sigma 85 f1.4 is the lens that gives you the highest bokeh capability while providing a reasonably usable angle of view, i.e more bokeh and pop than what the DA*50-135 can do @ 135mm f2.8. The DA*200 SDM would be a bokeh killer on a full frame camera, but the angle of view makes it difficult to use with the K-3 for other than head and shoulders type photos.
Best regards
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Forum: Post Your Photos!
02-06-2016, 12:04 PM
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Some of the prettiest, most vibrant sunsets on the Gulf. Nice state park here but they started playing around with their reservation system and got it so screwed up that it may never get fixed. Still, the view from the campground (last two shots) are pretty nice. Really like the lens.
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Forum: Pentax K-3 & K-3 II
02-08-2016, 02:48 PM
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(Not a real owl, I'm afraid.)
I recently got a K-3 II so thought I'd do a pixel shift test and post it with comparison 1:1 crops in case anyone wants to see some of those. Although this pixel shifting has been around for a while it's still a new concept to me! It was also an excuse to try out the wife's photo studio box.
I used Pentax Digital Camera Utility (PDCU) 5.4 as outlined by the Pentax Forums K-3 II review here. No lens correction or other changes were applied. For the non-pixel shift shot, I used PDCU's standard sharpening mode (the fine sharpening mode wasn't helping in the same way it does with pixel shift shots and seemed to be having an undesirable effect), and applied as much of this standard sharpening as I could before angled edges got very obviously pixelly/jaggy.
The lens is the HD DA 20-40mm at 36mm focal length, F16, 1/3 sec exposure. As an aside, I also took a shot with the wife's SMC DA 35mm F2.8 Limited Macro, and my 20-40mm zoom seems to match it for detail here in this non-macro shot.
The overall shot sampled down which I include just for context, not quality:
The 1:1 crops:
I'll try using it in non-perfectly stationary scenes - I'm mostly interested in landscape photography - and see how PDCU and dcraw (modified version as discussed at this forum) deal with the bits that aren't stationary. I understand that they both attempt to use the data from one of the four RAWs in those areas which contain motion in order to avoid artefacts.
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Forum: Pentax SLR Lens Discussion
02-06-2016, 05:28 AM
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Fortunately, these are not essential for the creation of good photographs, no?
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Forum: Pentax SLR Lens Discussion
02-06-2016, 04:28 AM
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K mount killing me softly:
Not a problem. Roughly speaking, as soon as you've got more than 2 or 3 lenses, the cost of lenses out-weight the cost of one camera body. Buy the lenses of your choice, then buy a camera body to mount on the lenses. If you are clear about why you want to use the lenses (LBA aside), you can invest in more than one mount and that does not necessarily cost more than when you upgrade a camera body from the same brand. There's still something that can bother you: switch back and forth through completely different menus and camera features from brand A to brand B.
In my case, I separate usage in two cases: all around camera system, and wildlife/sport dedicated system. For wildlife, I'd still have an interest with a fast APSC camera, the K-3 would do it, but I would get the k mount DA560 long lens (which I think is a 400 f4 with a x1.4 TC optics on it, so too expensive for what it really is). For instance it would be a 500 f4 mounted on a 7DII or D500, I could benefit from the crop factor and speed of the lens aperture and AF. For the all around system, I could sell all of my apsc Pentax system and upgrade to a Pentax FF, although I don't know yet what the specification might be , and I could still consider a FF mirroless for the small size and the fact that I know I don't need a fast AF for lanscape/archi/portraiture, but I could benefit from the better IQ of the sensor and portability.
In the optimistic case that Ricoh will continue to support and develop Pentax, they certainly are and are going to provide high quality lenses to cover most use cases from wide angle to tele, but not likely anything supertele for a long time. As a photog, that should cover all your needs, but obviously would not fulfill your LBA "wants" but that's another issue (some people end up collecting several dozens of lenses while actually not using them). If you haven't contracted the LBA virus, with three lenses and a Pentax FF + Pentax APSC bodies , you can already cover most use cases.
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Forum: Weekly Photo Challenges
02-01-2016, 05:52 PM
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This is a very important subject and I'm glad you chose it for the theme for this week's Weekly Challenge, Superduper. My photo is distasteful, makes me sick whenever I think of the circumstances under which I found the scene, but I think it's worth posting anyway. While hiking in a favorite place, I smelled it before I saw the large pile of butchered animal pieces. They were fresh and piled high, bits of wild geese, beaver, muskrat, whitetail deer, and turkeys, and probably other animals. They'd been dumped all at once from the back of a trailer, probably, hauled by an ATV, on public land, just inside the woods. It's gruesome enough as is, though scavenging animals welcomed the bounty, but to make it a particular example for this contest is that the animals whose parts are here were killed well outside legal hunting season.
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Forum: Weekly Photo Challenges
02-01-2016, 12:23 PM
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I live in a place that does not recycle. All food garbage, cans, bottles and paper etc. are landfilled. The township only separates out the metals to sell. It was the hardest thing to get used to after moving from a city that recycled everything including household compost.
However, the dump is an interesting place to visit and can offer a study (and photo opportunities) of human and animal behaviours. It sits on right on the doorstep of the Algonquin wilderness of over 7500 square kilometres. The dump is half way up a massive ridge and a view to the south is of hills, valleys and trees. The ridge gives rise behind this pile of garbage to another vista, and a view of wilderness as far as the eye can see in all directions. Wildlife such as vultures, gulls, hawks, eagles, weasels, martins, wolves and bears are frequent visitors to the dump.
I think the bears are impacted the worst as they become habituated to people and their garbage, and then are killed by hunters who set up bear baits and sit in tree stands. To be frank, it makes me sick when I am exploring the bush and I come across one of these scenes. I know the local outfitter killed 5 bears this fall right in this area. (I might change this photo before the end of the contest. I have several to choose from but on another computer.)
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Forum: Pentax SLR Lens Discussion
02-02-2016, 03:41 AM
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Isn't this Forum special! (I mean the membership, of course)
Well done Dewman. You rate!
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Forum: Pentax SLR Lens Discussion
02-01-2016, 10:43 PM
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There's a very interesting story that's connected to the lens give-away I had a few weeks ago that I thought you all might like to know about.
Mark Jerling, a member her on PF mentioned that a young lady he knew, young Miss May K would like some of the lenses.
He lives in New Zealand.
She lives in Missouri.
I sent her four or five of the lenses.
I live in Idaho.
But, the young lady didn't have a camera to go with the lenses, so I found a Pentax *istD L on a Craig's List ad .....
.....in San Diego.
The woman who sold it to me lives in Lebanon.
She had taken the camera to The Democratic Republic of the Congo during a Peace Corps. stint.
When I got the camera, it didn't have a memory card and I couldn't find a 2 GB card for it. BigDavePhoto, a member here on PF heard of our plight and graciously sent one to me.
He lives in Indiana.
It arrived today. I slipped it into the camera along with some AA batteries and BINGO! The camera works like a charm!.
So, tomorrow, I'm going to get it packaged up and sent off to young Miss May K, so she can begin her photography quest and post some photos for us!
Wow! What an around-the-world adventure this has been! :lol:
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Forum: Flashes, Lighting, and Studio
02-01-2016, 12:09 AM
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If you are having a hard time coming up with ideas: you are overthinking it. Photographing flowers* is very easy. As i'm sure you know there are plenty of techniques: wireless flash, fill reflectors etc, etc, so on and so forth. I'll mention Light painting as another technique you might want to look into:
Pentax K10D - FA*200mm f/4 ED Macro ISO 100 10s f/11
Pentax K10D - FA*200mm f/4 ED Macro ISO 100 10s f/11
Both of the images above were taken moments apart, but with light painting you have the ability to light parts of your subject as broadly or as selectively as you want.
Painting with light is technically undemanding, all you need is your camera set up on a tripod, a remote release( self timer will work too), a suitable cut flower, a darkened room, a good flashlight ( preferably with an adjustable beam angle), some black velvet for a background - or you can create a white background by simply overexposing some grey card. Painting with light can let to get really creative.
I avoid using reflectors if I can: they are often a pain to position and on windy days using them is categorically not-an-option. I prefer flash for multiple reasons - motion stopping ability, flexibility with light quality, and convenience. Unfortunately Pentax P-TTL isn't anything like Nikon CLS, so you will want to work manually with reliable flash triggers. Working with wireless manual flash with the Pentax system is a bit of a pain as you have to manually input your lighting ratios on each flash unit - so the more of them you have: the longer a shot will take to set up. I prefer to keep it simple, and often one light is all you really need.
Pentax K10D - Pentax FA*200mm f/4. ED [IF] Macro 1/180th f/5.6 ISO 100 wireless AF540FGZ + Sto-fen diffuser.
With reflectors you don't have the issues you have with flash but they have their own set of annoyances, you need stands** to hold them, and prevent them from becoming airborne, and packing them up can be tricky*** but the principal advantage of working with sunlight is that is costs practically nothing, but you are a slave to the weather. I'm all for using available light: it is just that some flowers are at their best during certain times of the day - but sometimes that time of day the lighting is flat,uninteresting or simply not working with the subject. It is in those situations where flash can really come in handy.
Pentax K5IIs - SMCP-K 50mm f/1.2 @ f/1.2 1/6400th ISO 80
*Also some plants have really interesting foliage - don't neglect it.
** Having voice activated light stands A.K.A photography assistants are very useful.
*** In my collection there is a particularly over engineered metal rimmed reflector that folds out rather energetically, one of my assistants put a sticker on the cover saying "warning: decapitation hazard"
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Forum: Pentax SLR Lens Discussion
01-28-2016, 06:39 PM
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Answering that Seattle's Best mug with something north of parallel 49
 1964 by Austin Smith, on Flickr
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Forum: Mini-Challenges, Games, and Photo Stories
01-26-2016, 01:06 PM
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The "new-to-me" FA 50/1.4 on K-5 ... xpost from Daily Challenge ...
 Chairs by Jean Poitiers, on Flickr
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