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Forum: Photographic Industry and Professionals 1 Day Ago  
16 Photography Documentaries every Street Photographer should watch
Posted By Dartmoor Dave
Replies: 11
Views: 1,599
Although it's not strictly about street photography, I'd also highly recommend the feature length documentary about Sebastiao Salgado, "Salt of the Earth". A great film about a master photographer, and about humanity at its worst and best.
Forum: General Photography 2 Days Ago  
Photography
Posted By Dartmoor Dave
Replies: 19
Views: 573
That particular photo doesn't do much for me personally but following the link led me to the work of Christy Lee Rogers, who I'd never heard of before. And wow! It's been a long time since I've stumbled across photography of such beauty and originality that it made me gasp aloud, but her work does. CHRISTY LEE ROGERS
Forum: Pentax News and Rumors 2 Days Ago  
New K-series DSLR under development to be exhibited
Posted By Dartmoor Dave
Replies: 2,979
Views: 182,050
Sounds like they're getting close to the ultimate digital camera: uses GPS to detect where you are, then consults a database of photos taken at that spot before to decide which composition will get the most "likes". Then it uses a gyrostabiliser and force feedback to position your hands or the tripod correctly for the shot, and will refuse to fire the shutter if you try to shoot from any other angle.

I almost added a :lol: at the end of that. But on second thoughts I'll go for a :(, because I've suddenly realised the inevitability of a camera like that actually coming along someday.
Forum: Pentax DSLR Discussion 4 Days Ago  
The K10D Club!
Posted By Dartmoor Dave
Replies: 4,995
Views: 478,237
Thanks, that sounds worth trying. I've never actually used DCU but I've still got the setup disc around here somewhere, so I'll give it a go.
Forum: General Photography 4 Days Ago  
Does that really add more value?
Posted By Dartmoor Dave
Replies: 93
Views: 1,529
It's made in the mind of the photographer while looking at the scene. Then the photographer uses whatever technical means are necessary to get the desired end result. A photographer who insists on doing it all using SOOC jpeg is merely placing unnecessary limits on the technical means that are available.
Forum: General Photography 4 Days Ago  
Does that really add more value?
Posted By Dartmoor Dave
Replies: 93
Views: 1,529
A few weeks ago, back when the weather was warm, I spent some minutes watching a keen photographer trying to photograph a group of Dartmoor ponies with his very high-end looking Canon on a tripod. The ponies would stand there patiently while he planted his tripod feet and adjusted the height, then at the moment he bent down to look through the viewfinder they'd move away out of frame. Each time the ponies did that the photographer moved his tripod to a new position and started setting up again, and each time he finally bent down to look through his viewfinder the ponies moved away. After about ten minutes of it the poor guy looked close to tears.

The thing is, ponies really don't like it when they can't see your face. So if you want to get good photos of them from close by you have to shoot handheld and shoot fast, with the camera up to your eye for the briefest moment possible. Of course you could try using live view and a tripod, although you'd still be most likely to end up with lots of photos of a horse's a**e and also look like one.:)
Forum: General Photography 4 Days Ago  
What is 'correct' exposure ?
Posted By Dartmoor Dave
Replies: 22
Views: 623
Like many members here I shot slide film for decades before digital came along, and in those days we all had to learn the skills to choose the right exposure at the moment of shooting because we didn't have any other choice. The fact that most of us now choose to shoot raw doesn't mean that we've lost that ability to choose the right exposure. We might well choose a different exposure for a raw file than we would for slide film, but in both cases we'd be doing the same basic thing of fitting the tones of the real world scene into the camera's available dynamic range to get the end result we want.

You can't expect any extra points for getting the exposure right in a straight-from-the-camera jpeg. As far as any old slide shooter is concerned, that's just demonstrating a basic level of competence no more significant than getting the shot in focus.:)
Forum: Pentax DSLR Discussion 4 Days Ago  
The K10D Club!
Posted By Dartmoor Dave
Replies: 4,995
Views: 478,237
Beautiful light there, Paul, captured with a nice moody feel to it.

Is it the default jpeg settings, or did you do anything special? I've been playing around with jpegs lately because the subject keeps coming up all over the forum, but so far I haven't found any combination of settings to wean me off my reliance on custom raw profiles. Which is kind of a shame, because to be honest I'm bored of spending time raw processing and I'd really like to go back to a more slide film like approach. It's a shame that DSLRs don't allow us to upload our own custom .dcp or ICC profiles to get the rendering we really want straight out of the camera.
Forum: General Photography 4 Days Ago  
Does that really add more value?
Posted By Dartmoor Dave
Replies: 93
Views: 1,529
Thanks for such kind words:). That one's actually a good example of what I meant by having to process a photo to make it more truthful to reality. The light really did look like that on that amazing evening, and I've never seen it come close to the same effect at that spot since.
Forum: General Photography 4 Days Ago  
Does that really add more value?
Posted By Dartmoor Dave
Replies: 93
Views: 1,529
I've been doing some SOOC jpegs over the past couple of weeks, since the subject has been coming up quite often around the forum recently. It turns out that, on all the digital cameras that I own, the colour rendering in straight jpegs is markedly untruthful to the real world scene when compared with the colours from my usual custom profiles with raw. And that renders the assertion that some people make, that SOOC jpegs are somehow more truthful, a false one to my mind.

I'd argue that there's an intrinsic inaccuracy in the default renderings from most digital cameras, using both jpeg and raw, and that if your goal is to take photos with some sort of verisimilitude to reality then processing to correct the camera's innate untruthfulness is the only way. And if correspondence to reality isn't your goal (it certainly isn't my goal in B&W), then what the heck. . . throw as much PP at it as you need to turn it into your own definition of beautiful.:)

Edit: Probably more relevant to this topic, when I post my own photos in a general photography thread I usually don't mention that they were taken with a 10 megapixel CCD, on the assumption that some people are likely to devalue them because of that.
Forum: General Photography 5 Days Ago  
Does that really add more value?
Posted By Dartmoor Dave
Replies: 93
Views: 1,529
Darn, I've been doing this photography thing all wrong. I thought it was about capturing some aspect of the world that's interesting and meaningful to the photographer, that he or she hopes might be interesting and meaningful to others too.
Forum: Pentax DSLR Discussion 5 Days Ago  
The K10D Club!
Posted By Dartmoor Dave
Replies: 4,995
Views: 478,237
I agree with Russ that your shot looks great with exactly the dynamic range it's got, Paul.

Speaking of dynamic range in general, I think the K10D sensor has really got at least a stop more range than the embedded raw profile makes it seem. The embedded profile applies quite a contrasty tone curve, and you can easily get a stop more out of the sensor just by switching to a linear tone curve if your raw processor allows it.

I always make two versions of my custom profiles, one with the standard tone curve that Adobe Profile Editor applies when it's creating the profile from the test card, and another with the linear tone curve option that the editor also lets you select. With the linear profile that I'm currently using when I need to, I can easily get two more stops of dynamic range than the embedded profile would manage. The B&W shot a couple of pages back is a good example -- it was only possible to do it from a single frame by using a linear tone curve, then bringing the contrast back up to where I wanted it to be in Silver Efex.

Here's a snap from July that I finally got around to processing. Lydford Church with the Takumar 17mm, defished and using a profile with the standard tone curve.

Lydford Church by David Holland, on Flickr
Forum: Non-Pentax Cameras: Canon, Nikon, etc. 6 Days Ago  
Confessions of a Toy Camera Shooter....Confess Here!
Posted By Dartmoor Dave
Replies: 2,249
Views: 182,649
No wonder the poor thing looks shy. I mean, was it even asked if it consented to that kinky rope bondage look? Try suggesting something like that to any of the ponies around here and you'll be lucky to get away without a hoofprint on your face.
Forum: Pentax DSLR Discussion 10-12-2019, 12:36 PM  
A supposition with a question.
Posted By Dartmoor Dave
Replies: 30
Views: 936
I'm just filled with happiness to see a thread about portraiture where someone wants more depth of field rather than less.:)
Forum: General Photography 10-11-2019, 02:54 AM  
What lenses are these on the ISS?
Posted By Dartmoor Dave
Replies: 20
Views: 614
Thanks Mike. Yep, I assumed you'd be the man who'd know:). I looked at that article when I was searching earlier, and it's a really fascinating read about the remote cameras used in the unmanned Soviet probes. It doesn't seem to cover the manned missions though, although I haven't had time to read it all the way through yet. I'll be looking at it again in more detail later.

I also found an old Amateur Photographer piece about a camera built for the Soviet manned moon landing project that never happened: ?Top secret? space camera turns up at auction - Amateur Photographer

I'm wondering if maybe that wonderfully kludgy looking Gomz Leningrad was the standard Soviet space camera, although the article isn't clear. It looks like exactly the engineering approach they always used in their space programme though: the Americans spent millions developing a pen that could write in zero gravity, while the Soviets used a pencil.:lol:
Forum: General Photography 10-11-2019, 01:18 AM  
What lenses are these on the ISS?
Posted By Dartmoor Dave
Replies: 20
Views: 614
This is making me wonder which cameras were used by cosmonauts during the Soviet era of spaceflight. An online search reveals basically nothing, since no matter which terms I use Google can't seem to believe that I'm not looking for info about NASA. So did the Soviets use Zenits? Or Kievs? Or something built specially for the purpose?
Forum: General Talk 10-08-2019, 09:36 AM  
What's it take to get on your "ignore user" list?
Posted By Dartmoor Dave
Replies: 54
Views: 1,080
I've set up a second account under a fake ID, with that annoying idiot Dartmoor Dave on ignore so that I don't have to read all the nonsense he spouts.
Forum: Pentax SLR Lens Discussion 10-08-2019, 02:50 AM  
Focal length = focal length, I know . . . . . . . . . . BUT
Posted By Dartmoor Dave
Replies: 131
Views: 2,335
My main conclusion as I bow out of the thread is that nothing that's been discussed will have any effect at all on the practical way that I think about depth of field when I'm doing my own photography. So I'm not sure that I've actually achieved anything other than to irritate myself and probably a few other people. Although I did end up making a really nice Spanish omelette for dinner last night.:)
Forum: Pentax SLR Lens Discussion 10-08-2019, 01:41 AM  
Focal length = focal length, I know . . . . . . . . . . BUT
Posted By Dartmoor Dave
Replies: 131
Views: 2,335
That's not really how it's done, but I'm happy to accept your overall argument that we can scale back from viewing size to sensor size in useful ways.:)
Forum: Pentax SLR Lens Discussion 10-08-2019, 01:38 AM  
Focal length = focal length, I know . . . . . . . . . . BUT
Posted By Dartmoor Dave
Replies: 131
Views: 2,335
For me the only question in all this has been whether or not the viewing size of a digital photo can be physically scaled back to the physical size of the sensor in any way at all. For my money, online depth of field calculators are so simplistic in the assumptions they make they are never going to be much use. My own approach has just been to have the final viewing size in mind when I shoot, and go by what I know works from experience with the lens I happen to be using. That's dependent on the CoC projected onto the sensor by the lens, the size of the sensor pixels, and also on the pixel size on my 24" 1920x1080 monitor -- which is about 0.25mm and of course displays a downsampled image.

And downsampling an image is not a simple arithmetical process. I've only got a very basic layman's understanding of it, but I have checked that understanding with my father, who designed computer graphics hardware for a living and was a member of mpeg before he retired. So I like to think he's a fairly reliable sounding board when I want to double-check if I'm understanding something correctly. My understanding is that in most cases, when you're looking at a digital photo, it's done by scaling the waveform and most definitely not by simple processes like skipping pixels. Which is why I still think that @Photoptimist is oversimplifying downsampling in his examples, even though I'm happy to go along with him in general that the CoC at the final viewing size does have a physical size, and so it is scalable back to the physical size of the CoC on the sensor.

I do accept your point that the pixels on a current generation sensor are small enough that we can think in terms of the physical size of the CoC on the surface of the sensor. So once we know the final viewing size, resolution, and distance we can then scale back in a meaningful way. But if people start asserting again that the viewing size of a digital photo is an optical enlargement in the same way that a print from a negative is then I'll be right back in the fray.:lol:
Forum: Pentax SLR Lens Discussion 10-07-2019, 02:22 PM  
Focal length = focal length, I know . . . . . . . . . . BUT
Posted By Dartmoor Dave
Replies: 131
Views: 2,335
The point that answered my own personal objections was:




I can accept that there are ways in which the final viewing size is scalable back to the original sensor size in digital photography, even though there is no optical enlargement taking place in the same way that it does with film, and even allowing for resampling and the fact that digital data itself has no physical size. It's quite a subtle distinction, but it does the job for me within the context of this thread.:)
Forum: Pentax SLR Lens Discussion 10-07-2019, 09:30 AM  
Focal length = focal length, I know . . . . . . . . . . BUT
Posted By Dartmoor Dave
Replies: 131
Views: 2,335
Thanks, and I'm happy to go with your beautifully clearly put explanation. You've convinced me that we can meaningfully make a connection between sensor size and final viewing size when it comes to depth of field, and I'm grateful for that.:)

Mmm. . . eggs. . . yummy. . . :lol:
Forum: Pentax SLR Lens Discussion 10-07-2019, 05:18 AM  
Focal length = focal length, I know . . . . . . . . . . BUT
Posted By Dartmoor Dave
Replies: 131
Views: 2,335
I've only had time to have another quick read through it over lunch, but I strongly agree with Gkramer that CoC makes more sense when stated in terms of the number of pixels it covers on the sensor than it does when stated in terms of physical size. Physical size is such an analog concept.

There's an awful lot of people in that LuLa thread refusing to acknowledge any difference between digital and film though. One guy even refers to Ansel Adams as an authority. About film, yes, an incontrovertible authority. About digital, not so much.
Forum: Pentax SLR Lens Discussion 10-07-2019, 01:40 AM  
Focal length = focal length, I know . . . . . . . . . . BUT
Posted By Dartmoor Dave
Replies: 131
Views: 2,335
Thanks for that link. I won't get time to read it in detail until later, but from a quick look I think I'm in complete agreement with Gkramer's original post, particularly on the question of "enlargement" and why we can't talk about that in digital photography in the same way that we do with film.
Forum: Pentax SLR Lens Discussion 10-07-2019, 12:33 AM  
Focal length = focal length, I know . . . . . . . . . . BUT
Posted By Dartmoor Dave
Replies: 131
Views: 2,335
I also find myself in the unfortunate position of not entirely agreeing with @Photoptimist, because I think he's oversimplifying how downsampling works in his example. But having said that, I know from experience that disagreeing with him can end up with me having egg on my face, because he actually knows a heck of a lot more than I do.:)

I do have to point out to Photoptimist though: The Windows 7 computer that I do my photo editing and viewing on has got no idea what physical screen size I'm using, but only the pixel resolution of the monitor attached. Nor does it have any idea what physical size sensor was used to take any particular photo, but just the pixel resolution. So any relationship between the physical sensor size and the physical viewing size is incidental rather than direct, caused only by the fact that each pixel on the monitor is far bigger than the pixels on the camera sensors (and the pixels in the monitor image are the result of downsampling too). And when we're talking about prints, I think we're better off sticking to non-interpolated prints of the full sensor resolution, because resampling algorithms are a factor better left out of a discussion like this.

Note to Photoptimist: I'll take the eggs on my face fried sunny side up, with nice crispy brown edges please. No doubt you'll be serving them up to me soon, with some math on the side.:)
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