I came to following observations:
1. With FF lens and K1 in 1:1 cropmode makes little sense as indicated
by others.
2. With APS-C lens and K1 in 1:1 cropmode, there can be the advantage
of using the whole image circle.
3. However, many lenses do not offer the whole image circle to the
sensor. First, the tulip-shaped sun-hood is optimized for maximum
shading. This can result in an image circle of roughly 3:2.
4. My Sigma 8-18mm has this and the hood is fixed to the lens so cannot
be taken off without damage.
5. Second, My Pentax-K 135mm/2.5 even w/o lenshood projects 3:2 on the
sensor, due to build in window to reduce unwanted reflections. This
is a FF lens, but I expect there will be APS-C lenses with a 3:2
window too.
6. For the optical view finder, the cropmodes are only an overlay with
thick border lines, with APS-C lens, this helps somewhat in judging
what will be in the final image.
7. APS-C crop mode on the live view display, fills the screen with the
image that will be recorded. That is better than the OVF
8. 1:1 crop mode (w APS-C lens) on live view display shows the image
limited in horizontal direction by the crop mode and in vertical
direction by the crop mode or by the lens, whichever is smaller.
Greetz, Jos
On 23-Oct-16 14:06, P.J. Alling wrote:
I know nothing about the 1:1 crop mode, so I decided to do a little
research...
After reading the first few posts on a Pentax Fora thread, I wanted to
yell at my computer screen: "IT'S CALLED AN IMAGE CIRCLE!"; idiots.
Like reading arguments by theologians about how many angels can dance
on the head of a pin, or theoretical physicists, about how many
possible sub atomic particles there are beyond the standard model.
Ultimately headache inducing.
Since I have no information let /me/ speculate wildly, or reason
rationally, whichever.
I assume you're using a full frame lens on the K-1. So I don't see
any particular reason to use crop mode on the camera. As you said the
files don't seem to be any smaller.
The 1:1 crop mode is designed to allow more sensor surface use with
the APS-C image circle, so once again, since I don't really know
anything, I'll assume that the firmware simply throws away anything
outside the 24mmx24mm square, much as it does the information outside
the APS-C crop, so it's not recoverable.
In fact given the performance improvements in APS-C mode, it is
probable that the camera really is only reading the center crop
portion. I have no actual data on the 1:1 mode but if there are
similar though not as great performance improvements then I expect the
same is true in this mode as in APS-C.
One or maybe two more assumption(s), the encoding is less efficient
for 1:1 crop mode because the job to get it included in the firmware
update was rushed, and the efficiency will be improved on the next
release. Either that, or since it's storing ~24mp worth of data, the
files are all on the small size for K-1 files and pretty much in the
normal range for biggish K-3 files, but you just didn't notice.
So there you go, in crop mode the data isn't recoverable because it
isn't there, and unless you're using an APS-C lens there's no real
advantage to using 1:1 crop mode*.
*I pulled all of this out of my ass, and standard disclaimers apply.
On 10/23/2016 2:37 AM, Larry Colen wrote:
When I was photographing a seminar at the dojo today, I tried
photographing in square crop mode.
On the bright side, it worked great for the photos that I was taking.
two people practicing Aikido can nearly fill a square composition,
where they leave a lot of the 3:2 frame empty.
On the down side, the raw files are no smaller. I also don't see any
easy way of recovering (in lightroom) the image that was cropped off
to either side, so the frames where someone's limb left the frame, I
would have been better off shooting uncropped.
If the square crop gave us 24 MP square images (rather than 36 3:2)
it would be awesome, it would save space on the card, and more
importantly in the buffer. As it is, all it saves me is selecting a
bunch of frames and cropping them square.
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