[peterh337]

I believe the Canon 5x has a button which can be programmed to do this.

It enables a rapid check of whether the photo just taken is in focus.

The only way I can see of doing this is to wind the nearer wheel ACW, during the instant review time (3 secs on mine).

[virusn3t]

I dont think so, but you can make the zoom go from "fit to screen" to 8x or 10x with one movement of the dial instead of small increments of 2x-4x-6x-8x etc.

[rawr]

Playback menu 1 > Quick Zoom > select 100%.

Once it's setup, 1:1 image review is as quick as: press play button, twirl rear e-dial one click.

[Not a Number]

On my K10D I can select the initial playback zoom - currently on my camera it is 2x. No need to use the eDial although you can still zoom in or out with the dial.

[peterh337]

That's brilliant - many thanks.

Curiously, 100% doesn't do it. One needs to set x16.

[Adam]

That's brilliant - many thanks.

Curiously, 100% doesn't do it. One needs to set x16.

16x is overzoom (i.e. you don't get any more detail, just a blown up look at the pixels).

[rawr]

Curiously, 100% doesn't do it. One needs to set x16.

There seems to be an in-consistency between the magnification steps available using Quick Zoom (X2/X4/X8/X16/100%) and the magnification steps available on playback (X1.4/X2/X2.8/X4/X5.6/X6.7/X8/X11/X16). On playback, X6.7 zoom is marked as delivering 100%, but in Quick Zoom, 100% is past X16.

16x is overzoom

Even 100% may be over-zooming it, particularly for RAW's, since all you are zooming into is a small JPEG preview embedded in the RAW.

[Tan68]

... X1.4/X2/X2.8/X4/X5.6/X6.7/X8/X11/X16 ...

somebody has a sense of humor

[Adam]

Even 100% may be over-zooming it, particularly for RAW's, since all you are zooming into is a small JPEG preview embedded in the RAW.

I don't think that's the case, doesn't the camera just apply Pentax JPEG settings on the fly as per the raw file? You can get much clearer details at 100% than half that, for instance.

[banep]

somebody has a sense of humor

Those zoom ratios are HILARIOUS !!!

I didn't noticed that earlier, but, but, but...there is f/10 between f/8 and f/11 which is equivalent of 100% view in playback mode.

[rawr]

doesn't the camera just apply Pentax JPEG settings on the fly as per the raw file

It could, I guess. But I think it would be too slow, esp with big RAW's. Much faster to display the pre-built thumbnails.

Running 'exiftool -s -G BLAHBLAH.DNG', where BLAHBLAH.DNG is a 24MB K-5 DNG, for example, reveals there are two tiny preview images embedded in the RAW - a JPEG and a TIFF:

...
PreviewImageSize : 640x480
PreviewImageLength : 36429
...
ImageSize : 4992x3284
LensID : smc PENTAX-DA* 300mm F4 ED [IF] SDM
Megapixels : 16.4
PreviewImage : (Binary data 36429 bytes, use -b option to extract)
ScaleFactor35efl : 1.5
ShutterSpeed : 1/1000
ThumbnailTIFF : (Binary data 57816 bytes, use -b option to extract):
...

I suspect one of those preview images feeds image zoom/ image playback of RAW's and JPEGs.

edit: I could be wrong.

Nikon NEF's seem to embed a higher res JPEG ('JpgFromRaw'), as well as a small preview JPEG '(PreviewImage'), another image ('OtherImage'), plus a small TIFF thumbnail ('ThumbnailTIFF'):

...
[Composite] JpgFromRaw : (Binary data 1354202 bytes, use -b option to extract)
[Composite] LensID : AF-S VR Zoom-Nikkor 70-200mm f/2.8G IF-ED
[Composite] LensSpec : 70-200mm f/2.8 G VR
[Composite] Megapixels : 24.5
[Composite] OtherImage : (Binary data 903165 bytes, use -b option to extract)
[Composite] PreviewImage : (Binary data 103399 bytes, use -b option to extract)
...
[Composite] ThumbnailTIFF : (Binary data 57816 bytes, use -b option to extract)

That 1.3 megabyte 'JpgFromRaw' is a pretty large JPEG, so a full pixel size JPEG may be living inside Nikon's RAW's.

It's possible that Pentax also embeds a large JPEG in it's RAW's just like Nikon does, and those big JPEGs are what you see during in-camera image playback. It could simply be the case that EXIFTOOL doesn't seem to be able to find and decode those big embedded JPEGs in the Pentax EXIF data yet.

[77me]

Try a PEF.

[Composite] JpgFromRaw : (Binary data 4257094 bytes, use -b option to extract)
[Composite] LensID : HD PENTAX-D FA 15-30mm F2.8 ED SDM WR
[Composite] Megapixels : 36.6
[Composite] PreviewImage : (Binary data 57424 bytes, use -b option to extract)
[Composite] ScaleFactor35efl : 1.0
[Composite] ShutterSpeed : 1/45
[Composite] ThumbnailImage : (Binary data 7491 bytes, use -b option to extract)

[rawr]

FWIW, it's also worth mentioning that in K-1 DNG's, the preview image pixel size is 720x480:

Preview Image Size : 720x480

which is certainly bigger than the K-5's 640x480, but 720x480 is still probably not large enough to generate a proper 1:1 image preview.

So either the K-1's RAWs are hiding a full-size 'JpgFromRaw' image within them, like the one Nikon RAWs include, or K-1 image playback is based on the small JPEG 'PreviewImage', or the K-1 does indeed dynamically generate full-size JPEG's from the RAW files every time the user hits the playback button. I still doubt that the latter is happening, but it's not impossible, I guess..

[77me]

DNG's have the jpeg from raw, but it is using the duplicate tag PreviewImage.

[Composite] ImageSize : 7392x4950
[Composite] LensID : smc PENTAX-DA* 55mm F1.4 SDM
[Composite] Megapixels : 36.6
[Composite] PreviewImage : (Binary data 4439436 bytes, use -b option to extract)
[Composite] PreviewImage : (Binary data 55027 bytes, use -b option to extract)

[rawr]

DNG's have the jpeg from raw, but it is using the duplicate tag PreviewImage.
...
[Composite] PreviewImage : (Binary data 4439436 bytes, use -b option to extract)

Aha. I think you solved the problem.

A 4.4MB JPEG is pretty large and probably 7392x4950 too, so hence useful for 1:1 previews.