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Forum: Pentax Forums Giveaways 09-07-2016, 10:44 AM  
PF 10th Anniversary - Pentax K-50 1-Day Giveaway! - Entries closed, winner announced.
Posted By Jerry_K
Replies: 1,825
Views: 73,894
Wish it was a K-1. I would gladly write an elaborate essay to win it, instead of just a short post.
Forum: Pentax News and Rumors 02-22-2016, 06:05 PM  
Full K-1 Spec list
Posted By Jerry_K
Replies: 781
Views: 88,580
That would be awesome. K1 would then score rather high in DXOMark (if it still means anything). I'm particularly eager to see sample photographs taken at the highest ISO. ISO 200k qualifies for a pretty decent astroimager (an "available light photography" taken to an extreme). Wonder what the noise is though, as a function of exposure time.
Forum: Pentax News and Rumors 02-22-2016, 05:42 PM  
Full K-1 Spec list
Posted By Jerry_K
Replies: 781
Views: 88,580
Does anybody know what exactly is the K1's sensor make and model? Could it be the same one as in Nikons D7xx/D8xx?
Forum: Pentax News and Rumors 02-19-2016, 10:37 AM  
Full K-1 Spec list
Posted By Jerry_K
Replies: 781
Views: 88,580
Full frame (36 x 25 mm) 36 MP sensor as the one K1 is equipped with has pixel resolution of 7360 x 4912. That means the effective pixel site is roughly a square 5x5 microns. For typical lens apertures used in normal cameras for mortal people (as opposed to CIA, NASA, science labs and some such) that means the diffraction limit is reached with Airy disk 4-5 microns in diameter. Therefore more pixels in full frame format is a boneheaded idea - there will be no more detail visible, period.

The proper way to higher resolutions is through bigger sensors. And here comes P645Z, or for those inclined to self inflict financial wounds - Phase One. This is the end of the road folks. The wall put there by the laws of physics. You can venture outside if you are rich or don't mind to become poor. But in the world of small format cameras - 36 MP is the upper limit with which we'll have to live from now on.

But that's not bad. Look how fine we ended up with microprocessors that hit the wall of 3 GHz. See? The sky is not falling. We'll be fine. Some stupid reviewers in stupid pseudo photo magazines may have to starve to death, but that's fine with me. Now we can concentrate on actually making photographs. :-)

---------- Post added 02-19-2016 at 12:05 PM ----------

Just to add to my previous rant/prophecy: I've always been a resolution freak in the most generic, Fourier transform sense, that is regardless of problem domain (spatial, measured in pixels or temporal measured in dB). That paradoxically drove me away from digital 10 years ago back to the realm of film photography. Scanning film at 3200 px/inch (highest reasonable resolution of my scanner and only slightly higher than the actual resolution of film, as it should be) I get 13.6 MP from 35mm film on still fabulous Nikon F5, 56.8 MP from freakishly awesome Pentax 67II and 195 MP from heavenly Wista 45 (4x5 format).

These 13.6 MP images can easily be printed at least up to 11x14 and that's what really matters. Film photography tought me that the point of making a photograph is to print it, not to convert it to a tiny, post stamp size blob of pixels left to die on some stupid facebook or other twitter.

Having said that I will gladly acquire K1. To pursue photography as an art it will contribute not the resolution (as my other cameras show, I have more than enough pixel real estate when I need it). What K1 has and film does not is the insanely high sensitivity. ISO 200k opens possibilities that previously were only abstract. Also, it appears to be a perfect camera for astrophotography. ISO 200k and no low pass filter! Yummy.
Forum: Pentax News and Rumors 02-18-2016, 05:44 PM  
Full K-1 Spec list
Posted By Jerry_K
Replies: 781
Views: 88,580
Upon reading the the max ISO value I had a brief albeit intense 1.21 jigawatts moment.
Forum: Pentax Medium Format 05-19-2010, 02:00 PM  
645D: high resolution pictures
Posted By Jerry_K
Replies: 13
Views: 3,327
Don't forget - the images were JPEGs, so looking at them in 1:1 magnification reveals JPEG artifacts more than any imperfections in details due to optics or digital in-camera processing.

Jerry.
Forum: Pentax Medium Format 04-21-2010, 10:22 AM  
Overpriced 6x7
Posted By Jerry_K
Replies: 6
Views: 1,937
That's horribly overpriced! I'd say that even for 67ii in pristine condition. The guy is off by at least a grand!

J.
Forum: Pentax Medium Format 04-07-2010, 12:10 PM  
Exposure compensation in P67ii
Posted By Jerry_K
Replies: 20
Views: 5,150
I want to do it just for the heck of it, out of shameless curiosity and to learn it. And also to play with Hugin software on Linux to see what it's worth. That's pretty much all my motivation :).

However I have to strongly object against bias toward "fantasy" pictures as somewhat illegitimate form of artistic expression. I do a lot of B&W photography and what is it if not a mere "fantasy"? After all, it can look realistic only to a dog. Even using some filters could be classified as making fantasy pictures. Same could be said about using Velvia instead of Provia or shooting a scene on an infrared film. I agree though that overdoing it may look nasty, but overdoing it is not my intention nor a stop along the path of my photographic development :-).
On the other hand HDR is the only way to squeeze biological eye's dynamic range into screen's or paper's dynamic range while preserving local contrast.

J.
Forum: Pentax Medium Format 04-06-2010, 06:01 PM  
Exposure compensation in P67ii
Posted By Jerry_K
Replies: 20
Views: 5,150
To be precise, what I want to accomplish is bracketing, that is to make identical photographs (in terms of the content to the last detail) differing only in the luminance received. Changing the aperture changes the content - the photographs won't be identical due to differences in the image caused by different depths of field. This is crucial for stacking frames for tone mapping or stitching frames to make panoramas.

From what you guys are saying it seems the only way to do it is to use the AP mode, however in that case I can't decide the initial (reference) exposure level; the meter will do it for me. And it will change it if conditions change from one shot to the next. Otherwise I have to use full stop only increments on the shutter speed dial (provided I'm not starting from 4 sec or 1/1000 sec extremes).

Jerry.
Forum: Pentax Medium Format 04-06-2010, 05:46 PM  
Exposure compensation in P67ii
Posted By Jerry_K
Replies: 20
Views: 5,150
Gary, what you've said makes perfect sense! Now it explaines why I had to turn the dial the "wrong" way in order to bring the bar to the middle. For instance, the meter says the scene would be underexposed at given shutter/aperture setting, which I would intuitively try to counter by adjusting Exp Comp dial to the + side. Not so, however. I have to turn it to minus side to bring the bar to the middle but all that accomplishes is that the Exp Comp dial barely shows me a measurment of how much I'm off of proper exposure.

Jerry.
Forum: Pentax Medium Format 04-06-2010, 05:25 PM  
Exposure compensation in P67ii
Posted By Jerry_K
Replies: 20
Views: 5,150
Of course. In manual mode I would expect the camera to vary the shutter speed from the reference value set on the speed dial. Like it does in aperture priority mode. The difference being: the reference shutter speed in AP mode is determined by the meter, while in manual mode it is determined by the user. Otherwise it's impossible to adjust (compensate) exposure by values smaller than 1 EV at any given aperture. For instance, on a shutter speed dial I can set the speed to either 1/500 sec or 1/1000 sec (which is a difference of one stop) but not to anything in between. I would also expect that my manually set combination of aperture and shutter speed defines a reference exposure from which I could deviate (in units of EV) by up to +/- 3 EV, but WITHOUT changing the reference.

Therefore, my question could be reformulated in the following manner: how do I do bracketing in manual metering mode by values being fractions of one step?

Jerry.
Forum: Pentax Medium Format 04-06-2010, 04:18 PM  
Exposure compensation in P67ii
Posted By Jerry_K
Replies: 20
Views: 5,150
Hi folks,

I just got a roll of Velvia developed on which a shoot a landscape with the intention of turning some frames into a HDR image and have some fun with tone mapping and such. To that end I took three exposures in manual metering mode with 0, +2 EV and -2 EV exposure compensation settings. Shutter speed and aperture were fixed. Yet all three frames came out identical. The user manual seems to suggest that exposure compensation dial works the same in manual and aperture priority metering mode. I found however an article on luminous-landscape.com that suggests this is not he case and exposure compensation works only in aperture priority.
So, how does it really work? Could it be that something is broken in the camera? Or do I do something wrong?

Jerry.
Forum: Pentax Medium Format 03-17-2010, 05:23 PM  
T-mount for 67
Posted By Jerry_K
Replies: 4
Views: 4,344
Oh, I see. So that special adapter is specific to a particular astronomical instrument? Is there a generic name for it? Is there a generic adapter that matches Pentax 67 bayonet on one end and has a 2" eyepiece dimensions on the other end?



As it happens I do own a pretty big SCT (Celestron CGE1400) but at f/11 it's hardly a fast instrument.



Given the size of the 6x7 film and the 4 meter focal length of my scope, an object the size of entire M31 could fit. Wouldn't that be nice? :-)

I did use a DSLR (Olympus E-500) on this scope, but it was nothing but a string of disappointments. Most of the time a got nothing, courtesy of impossible to turn of noise removal "feature" of that Olympus.

Jerry.
Forum: Pentax Medium Format 03-17-2010, 01:13 PM  
T-mount for 67
Posted By Jerry_K
Replies: 4
Views: 4,344
Hi guys,

Is there such a thing as T-mount for the 67 bayonet? I'm asking this question with astrophotography in mind but having the possibility of using various T-mount lenses would be nice too. I'm aware of the company called Hutech that makes a focuser and a mount for Pentax 67 but it's really an adapter to a 35mm T-mount, not the real thing. Pentax 67/67 ii is still going strong among astrophotographers so I think they must have had a way to attach the camera to a telescope, in particular to 2 inch eyepiece tubes, which makes most sense given the 67's bayonet diameter.

Jerry.
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