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06-29-2012, 09:32 AM   #1
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Why can't Pentax make a camera with exact 3:2 ouput???

I just wanted to share this mini-rant, and see if anybody has suffered the same annoyance.

Why in the world can't Pentax make their DSLR's output true 3:2 images? Whenever I process my images for 4x6 prints, I have to crop them because the files are just a teeny, tiny, little bit wider than a perfect 4x6. If I don't' crop them, then the site I use to print my 4x6's gives me a dialogue to auto-crop the pictures to a 4x6. But besides that, I just want my 4x6 files to be a true 4x6, just as I want my 5x7 and 8x10 files to be the exact ratios.

This is true of my K-x, and I was hoping that it was just a fluke to that particular model. But I just checked a sample image from the K-30, and the problem is even worse. I then checked some K-5 sample files, and found that they are the same dimensions as the K-30. Here are the numbers:
Pentax K-x: 4288x2488 pixels, 16 pixels wider than a true 3:2 ratio
Pentax K-5/30: 4928x3264, 32 pixels wider than a true 3:2 ratio
Before purchasing the K-x, I briefly owned a Canon t2i. I've gone back and checked those files, and they are 5184x3456, for a true 3:2 ratio. And by way of further condemnation of Pentax in this matter, I would point out that my Olympus PEN E-P1 Micro Four Thirds camera outputs a perfect 4:3 ratio.

So what gives? Am I the only one annoyed by this? I don't ever remember seeing it mentioned on here or in any professional reviews.

06-29-2012, 09:43 AM   #2
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Well I'm not sure about the exact pixel count; being right on or just a bit over/under, but...

For the Pentax K-01 the counts are as follows; for the 3:2 ratio

for 16m it's 4928x3264 - much like the K-5


for other file sizes...
12m 4224x2816
8m 3456x2304
5m 2688x1792

But now that I'm thinking of it, what camera out there does have a perfect 3:2 ??
06-29-2012, 09:56 AM   #3
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QuoteOriginally posted by Medium FormatPro Quote
But now that I'm thinking of it, what camera out there does have a perfect 3:2 ??
As mentioned above, the Canon t2i, which I briefly owned, had perfect 3:2 files. (And my Olympus has perfect 4:3 files). What rationale is there for not going with an exact 3:2 file, especially since they know that 4x6 photos are the most common print size (at least in the US...I have no idea about elsewhere).

I can understand if the sensor is not exactly a perfect 3:2 ratio, but it would be so easy to have the few extra lines clipped off in firmware.
06-29-2012, 10:09 AM - 1 Like   #4
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Edgar,
You're not the only one - i reported it previously on this thread:

https://www.pentaxforums.com/forums/pentax-k-5/180462-k5-aspect-ratio-not-1-5...-problems.html

It has cost me money and time before i knew what the problem was. I thought LR was messing me up initially, but that was not true, its a Pentax feature . Actually, its a feature of the Sony sensor perhaps. But one would think Pentax could trim it in their firmware. If they can do horizontal leveling - one would think they could size the frame size

To fix its fairly easy. LR shows the aspect ratio as Original in their crop tool window. Select 2:3 ratio, apply it then close the window, and its trimmed unnecessary pixels. But before i found the problem, the canvas printing company was charging me $5 to crop it. On a 30" to 36" print, the size difference over a true ratio is about 1/4". Standard Stretcher bars for canvas come in 1" increments so it becomes a big deal.

06-29-2012, 10:19 AM   #5
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Just revise your ruler to a hexadecimal scale and stop using a medieval English king's thumb for print composition ratios. Break free from the surly bonds of ancient proportions and the economy of standard print sizes dictated by paper manufacturers and let your images soar to as yet unimagined (uuh, an' expensive?) custom frame sizes.

The good news is that tweaking the crop gives you the opportunity to question whether a pure 3:2 ratio (or 4:5 or 5:7 or whatever) is an ideal choice for that particular image -- standard frame sizes notwithstanding.

H2

[ If I were king, I'd prohibit publishing any image at the arbitrary proportions of the camera sensor format without a witnessed certificate stating that specific composition had been critically analyzed and determined to be the esthetically ideal choice -- on pain of flogging. I've always appreciated that the 6x6 cm film format forced you to make composition choices in the viewfinder and on the enlarger easel. ]
06-29-2012, 10:22 AM   #6
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It is not the fault of the image file, it is the printing facility as I was told, if you print the 4x6 size print with borders, it is fine. If you print without borders then you lose a small portion of the image all around.
06-29-2012, 10:26 AM   #7
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I appreciate the sentiment pacerr, but here in the states 4x6 is the only print size that is reasonably priced. You can usually print 4x6 for 10 - 20 cents, but the next size up, 5x7, is usually anywhere from 70 cents to $1.50 each. So what sense does it make to have the camera output files that are 99.99% of the way to the standard size, but not quite?

I shoot RAW and process my images in Photoshop, and I crop to taste and frequently into various sizes/aspect ratios, but the odd ratio is still a completely unnecessary annoyance that will affect some users much more than others.
06-29-2012, 10:27 AM   #8
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QuoteOriginally posted by aleonx3 Quote
It is not the fault of the image file, it is the printing facility as I was told, if you print the 4x6 size print with borders, it is fine. If you print without borders then you lose a small portion of the image all around.
It's predictable that trying to fit a 1.51:1 shape into a 1.5:1 box will cause problems.

06-29-2012, 11:04 AM   #9
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I'm not downgrading your complaint because I often find myself settling for a white border to print an entire image from my K-r on 4X6 paper. At the same time, perhaps the following will give you a slightly different perspective.

One of the things I just looked at was standard photo paper sizes for both U.S. and metric. The only 2:3 sizes I see are 4"X6" and 10X15cm ... every other paper size in my printer setup has a ratio different from 2:3. While I recognize that 4X6 is probably the current favorite, it wasn't always so, and likely won't always be. For most of my SLR photography days, 3.5X5 was the most popular snapshot size - and it still is if you want to print 4 images on a single sheet of 8X10 or 8.5X11 paper. In my darkroom days, I had a paper holder designed to do four 3.5X5 images on one 8X10 sheet.

Then there is the viewfinder crop found in many non-pro SLRs. In my K-r, I can only see 96% of what will be recorded ... that pretty much means that I can make my 4X6 borderless print and still get everything I saw in my viewfinder.

And finally we have the Shake Resistance (SR) feature. By design, not every pixel on the sensor is intended to be printed. The sensor (or in other brands the lens) jiggles to minimize motion blur. Some pixels at the sensor edges will potentially be eliminated screwing with the ratio a little bit. Fair trade-off in my book.
06-29-2012, 01:39 PM   #10
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QuoteOriginally posted by Edgar_in_Indy Quote
. . . 4x6 is the only print size that is reasonably priced.
Yeah, I understand the economics, but to allow the price of the cheaper 4x6 print to drive the frustration of dealing with a tiny percentage of pixels in the image size (when there are so many other factors as noted in part by J.J. ) doesn't appeal to me. If printing/sending "drugstore snapshots", finessing the edges isn't even going to be noticed.

If the image deserves attentive color tweaking and a compositional crop I don't feel bad about a little extra cost to "upgrade" the print and I don't begrudge the extra margin "waste".

With the exception of a true "pro" VF like the LX and some of the medium format bodies, I've never considered the image seen in the VF as sacrosanct and always expected to crop for some reason in post-processing, wet or digital, as an accepted part of the equipment capabilities and limitations.

If you're not talking about hi-value prints, most of the PP software offers a customized match size to print option which, if set to 4x6 format, provides an "automatic" re-sampling which could only be noticed when doing a direct comparison of the original and the re-sampled files. Saves a lot of time and can be batch converted as well.

Simply copying to a new 4x6" canvas and dragging the borders offers a convenient way to assess the crop to maximize the image size even when printing borderless. When printing "convenience" prints on a 4x6 Epson PictureMate, I nearly always crop to some extent for composition and consider the margins (the waste?) the price of improving the composition beyond the nominal 2:3 sensor/printer format.

That's just my personal preference an' perhaps that comes from beginning with a square, 6x6 film negative which was inevitably going to end up printed as anything but square.

Also, consider that you can "jumbo size" two 4x6" images onto an 8.5x11 canvas either for slightly larger image size or borders for the cost of a single 8.5x11 print. Other combinations are possible and sometimes real bargains during print sales.

I print ALMOST everything (stuff that doesn't warrant specialty paper) on 8.5x11 paper. Bought in larger quantities on sale and considering the advantage of storing and handling and "learning" only one paper size it's more economical and with a little planning composite prints minimize waste even with unusual compositions.

H2
06-29-2012, 07:14 PM   #11
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Alrighty then...so I guess the predominant attitude is "Long live the almost-but-not-quite-3:2 aspect ratio!" Ah well, I guess I'll just continue to suffer in silence.
06-29-2012, 09:34 PM   #12
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Even if you 'won' here with the rest of us peons you'd still not win with Pentax.. since I doubt those responsible for such elements bother here much..

I can sympathize with the frustration. surely this could be adjusted in the firmware...
06-29-2012, 11:37 PM   #13
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Does any camera on the market create its images in the exact aspect ratio as advertised?

I'm completely willing to be corrected, but I suspect that every camera, film or digital, produces images that are a few pixels off from perfect ratio.

The sensors in all cameras have an 'absolute' resolution and an 'effective' resolution. The former is the physical size of the sensor. The latter is an adjusted value denoting the size of the image that will be recorded with the camera body specified. Sensors are not made for a single camera model (typically), and in each implementation there are physical variances that will affect the size of the image projected upon the sensor.

For example: The K20D's sensor measures 4688 x 3124 (1.5006:1). It produces images sized 4672 x 3104 (1.5052:1). That same sensor in a different camera body might produce images of 4607 x 3055 (1.508:1).

The bottom line is, you should always crop your images before sending them off to print; even if you're printing in the 'native' aspect ratio.
06-30-2012, 04:11 AM   #14
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I never actually thought about it, I do not print much.
the another Pentax, the Q has perfect 4000x3000 resolution.
Canon 60D/650D = precise 3:2, Olympus E3 = perfect 4:3 , Nikon D7000 = same as Pentax, a bit over ,
Nikon D800 a bit under, interesting......
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