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Forum: Pentax Full Frame
12-12-2019, 10:04 PM
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Agreed! I have been having modest success at such for about 50 years.
Steve
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Forum: Pentax Full Frame
09-03-2014, 11:06 PM
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I love my Sabatier...all 9 inches of it. I also love my 3 inch Mundial. The Mundial sucks for cutting watermelon though and cutting/coring apples with the Sabatier is tedious.
Steve
---------- Post added 09-03-14 at 11:13 PM ----------
I have a 3" Victorinox with locking blade that works nicely for many things, but watermelon...nah...won't go there...
Steve
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Forum: Pentax Full Frame
08-27-2014, 04:41 PM
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I should elaborate. As one of my more arcane practices, I shoot 4x5 large format. I own a Rodenstock 150mm f/5.6, which is considered a "normal" lens for that format. Are my images taken at f/5.6 with that lens magically transformed to be an equivalent to a FF (36x24mm) image taken with a 50mm f/2?*
Put another way, assuming that a 4x5 digital sensor with the same pixel density as used by the Sony A7s existed (~170 Megapickles), would the two lenses and systems be fully equivalent image-wise?
In less theoretical terms, say I scanned a fine-grained ISO 100 negative at 94 pixels/mm* to yield a 108 Megapickle image (12000 x 9000 pixel dimension). At 94 pixels/mm, digital noise on the scanner is negligible (linear array). Additionally, visible film grain at that resolution is similarly negligible. I know we are talking apples and oranges here since what I just described is a signal to noise ratio that is pretty high. Given that the A7s has an approximate linear pixel density of 119 pixel/mm would you consider the two systems to be equivalent with the Sony at ISO 100? If not, how many stops penalty are we going to assess the 50/2 in this comparison.
Is it possible that the notion of equivalence is not so well-defined outside the APS-C/FF debate and is based on a very narrow set of assumptions regarding sensor performance characteristics? Is it also possible that my 4x5 with the 150/5.6 offers little benefit over 24x36 FF other than capture resolution and dismally narrow DOF? Oh, I also forgot the cameras movements. ;)
Steve
(...continues to wonder how the word "stop" came to be assigned to so many things photographic...the 4x5 is two stops larger format than FF?)
* Similar DOF and FOV (cropped on the short axis to 3:2 ratio). Absolute aperture size is the same for both lenses meaning that the same amount of light will pass through both lenses for a given amount of time. I might mention that the 150/5.6 has an image circle somewhat larger than the 4x5 frame cropped to 3:2 ratio.
** The real world max resolution for my scanner. I never scan that high for 4x5; the files are too big.
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Forum: Pentax Full Frame
08-27-2014, 02:38 PM
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Apparently!!! The very next comment!
As I said...It as so counter intuitive...
?????? If you say so, Jay. Remember, I am one of those guys who is firmly in the "would really like a FF" camp.
This is where the discussion goes into stuff like "flux per pixel site" or something like that.
I personally believe that photographic film offers the highest potential return on a per photon basis. What could be more atomic than individual atoms?
Steve
(... is there a physicist in the room? The smoke is getting (predictably) thick in here...)
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Forum: Pentax Full Frame
08-27-2014, 08:15 AM
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Yep, my calculation is that the equivalence is closer to f/4 at the long end.
OTOH, why is this a bad thing? At 135mm on APS-C you get:- 200mm (FF equivalent) FOV!
- f/2.8 aperture for exposure purposes!
- f/4 (FF equivalent) DOF!
It looks like the classic validation of the APS-C advantage with longer focal lengths. The traditional challenge for 35mm film photographers with lenses over 150mm has been adequate DOF (accurate focus is a huge challenge) and low light capabilities. You can have one or the other, but not both.
Is this where the great cry of sensor equivalence is raised?
Steve
(...not much of a long lens shooter, but appreciate the advantage for those that are...)
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Forum: Pentax Full Frame
08-27-2014, 07:34 AM
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I am good at not answering the question that I am not answering. :D
Steve
---------- Post added 08-27-14 at 07:36 AM ----------
ROFL
:lol::lol::lol::lol::lol::lol:
Steve
---------- Post added 08-27-14 at 07:37 AM ----------
Dang, I hate this equivalence stuff! It is so counter-intuitive...
Steve
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Forum: Pentax Full Frame
08-23-2014, 10:50 PM
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I have a pair of film scanners that I use and have no experience with this technique.
Dang! That is a difficult to thing to explain. The short answer is that neither your monitor nor most (all?) printers is capable of native display of 14 stops of dynamic range with full tonality. A quality scanner is generally capable of dealing with the full range of negative density, though it may require some tweaking or even multiple passes to do so. Part of the magic of a good scan and expert printing (you may also add traditional darkroom printing) is the art of working with the range of light.
Did I do a good job of not answering that question?
Steve
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Forum: Pentax Full Frame
08-23-2014, 11:22 AM
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I don't own a FF digital, but I feel much the same in regards to my film work.
Steve
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Forum: Pentax Full Frame
08-23-2014, 07:48 AM
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To continue a little off topic and as a current film photographer, I will chime in here. Your understanding is definitely accurate in regards to highlights and only partially accurate for shadows. Current digital cameras have better dynamic range than past models (about 12 stops* for the K-3 at base ISO), but still clip at both the high and low ends of the value scale.
The better color negative films (e.g. Kodak Ektar 100 and Portra 160) will support 12+ stops of dynamic range with a high tolerance for over-exposure. Color slide films traditionally have somewhat less range (about 8 stops). B&W negative films can support 14+ stops with appropriate development techniques. Forum user Tuco regularly produces film images with elements spanning a huge dynamic range while maintaining detail and pleasing tonality throughout.
Yo Tuco's Pyro B&W on Flickr
Steve
* Dynamic range is generally expressed as "stops" of exposure or as EV, though some (following Ansel Adams) will use "zones".
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Forum: Pentax Full Frame
08-22-2014, 08:20 AM
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...and people wonder why I still keep my Jupiter-9 even though I have a FA 77 Limited in the bag... ;)
Steve
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Forum: Pentax Full Frame
08-20-2014, 05:06 PM
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Pixels are what the picture is made of. The final output device "knows" nothing of pixel pitch. For equivalent aspect ratios, resolution is the number of pixels to produce the image. There truly is nothing more. FOV, OTOH, is determined by frame size and focal length alone. Now if you are going to crop a FF image to APS-C size to get FOV equivalence from the same lens on a K-3...yes, that would require a 50+ megapickle sensor, but who in their right mind would do that?
Steve
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Forum: Pentax Full Frame
08-20-2014, 08:49 AM
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I don't have experience with the Samyang, but in the last day or so I have judged four photos for the PEG taken with the DA 15/4 Limited. The DA 15 is a decent lens (I have shot with it), but three of the four were sadly soft at other than the center to the detriment of the photo. This may have been a reflection of the technique used or maybe it just proves the point that it is very difficult to produce a good rectilinear lens below 24mm focal length, regardless of format.
Steve
---------- Post added 08-20-14 at 08:54 AM ----------
Absolutely! Snapshot film cameras were designed around the knowledge that nobody was going to print larger than 4x5.
Steve
---------- Post added 08-20-14 at 09:04 AM ----------
Yep...All the more reason to buy a 645Z ;)
That response is a little tongue-in-cheek since in the real answer is that many current FF cameras meet or exceed the resolution of the K-3. In the digital world 24 Megapickles APS-C resolution is the same as 24 Megapickles FF (36x24) resolution. There are nominally the same number of pixels on each axis. The K-3 image is composed of 6016x4000 pixels while the Sony A7 (FF) image is composed of 6000x4000 pixels.*
Steve
* The pixel dimensions for my scanned 35mm negatives are somewhat less than that :(
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Forum: Pentax Full Frame
08-18-2014, 06:32 PM
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Thanks for the perk! I don't know about FF digital. The shots I posted (about half) were originally shot on film. The remainder with various lenses on APS-C.
Steve
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Forum: Pentax Full Frame
08-18-2014, 05:15 PM
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Yes, I got the joke. I should have included a few smilies as well.
Steve
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Forum: Pentax Full Frame
08-18-2014, 05:01 PM
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Beautiful and compelling landscape work. A ton of great APS-C landscape work has been posted on this site and elsewhere on the Web. When I saw yours, I was immediately reminded of Keitha's (Aravis') work. Yours has the same expansive quality.
Where I have been challenged is on the wide end, specifically finding a workhorse wide-angle (28mm f/2.8 equivalent) with excellent build and optics that is also compact and light. The DA 15/4 Limited is a great lens, but it is just a little wider than I would normally like. It also is a little pricey. I fill that slot with the Zenitar 16/2.8 fisheye (used in several shots above). It is a little quirky, but you manage with the tools you have. I also am very fond of the 35mm focal length on film. There are not many 22mm -24mm options out there for APS-C.
Steve
---------- Post added 08-18-14 at 05:04 PM ----------
Gosh, I like it when people start showing their photos! There is so much great work out there.
Steve
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Forum: Pentax Full Frame
08-18-2014, 04:42 PM
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Beautiful photos Jay! As you may remember, I am solidly on the side of using a larger format for many subjects. I would love to have a FF digital camera.* I would point out, however, that all of your examples involve ultra-wide-angle lenses. As has been discussed multiple places, the balance shifts somewhat when doing long lens or macro work. The Crocosmia shot I shared above (done with the K-3 and Sigma 17-70/2.8-4) would required a lens change to some sort of macro setup if done with a FF camera rather than my standard walk-around zoom.
Steve
* I seriously considered the Sony A7 before purchasing the K-3, but was put off by the noisy shutter and jello in the viewfinder.
---------- Post added 08-18-14 at 04:47 PM ----------
The Samyang 14/2.8 might be close enough, don't you think?
Steve
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Forum: Pentax Full Frame
08-18-2014, 04:27 PM
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...and I could not have made any of them without a camera.
FWIW, I would like to have the option of a K-mount FF digital camera for the same reason why I sometimes shoot medium or large format film. That being that there are times when it would be the right tool for the job.
Steve
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Forum: Pentax Full Frame
08-18-2014, 02:29 PM
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Thanks! The point I am trying to make is that, yes, it is possible to tell which are which for many of the shots if you know what to look for, but for the most part a decent image was made that satisfied the photographer (me) and expressed the artistic goal without regard to the tool used.
That being said, the wide-angle landscapes are much more approachable with non-specialized gear with the larger format and several of the flower macros were much easier to manage with the smaller format. I was tempted to throw in a few medium and large format shots along with a couple of phone images, but thought better of it :o
Steve
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Forum: Pentax Full Frame
08-18-2014, 02:19 PM
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Yes, yes, and yes...
Steve
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Forum: Pentax Full Frame
08-18-2014, 01:47 PM
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I have PHOTOS!!!
Here are a bunch of scans of FF 35mm film images mixed in with a selection of APS-C from my Pentax K10D and K-3. Note: This is not a contest, exif is intact on all photos. Some may have been easier to do on FF and others easier on APS-C.
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Forum: Pentax Full Frame
08-18-2014, 11:33 AM
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More space for pixie dust...
Steve
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