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09-22-2010, 01:40 PM   #256
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QuoteOriginally posted by falconeye Quote
Now that I look at the cut model again, I think it is from a K-5 indeed and I discover 2 interesting details:
  • The shutter box has an absorber pad in the bottom.
Hmm, are we possibly assuming that this is an attempt to address the mid-speed shutter blur noted on the K-7?

Can anyone post a K-7 cutaway for comparison?

Cheers!

09-22-2010, 01:45 PM   #257
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The cut-out looks like K-5 based in this exploded view. SAFOX IX+

Last edited by Kenn100D; 09-22-2010 at 01:46 PM. Reason: s like
09-22-2010, 01:53 PM   #258
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Pentax 645D photographs

Just for fun, some 645D photos I took Monday.

Enjoy!





09-22-2010, 01:58 PM   #259
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What is what around the pentaprism in the cutaway photo?
Something in the rear bottom, something in the rear top, something in front, and is there also something on top?

I can think of info row, af-points, light meter, but then what?

09-22-2010, 02:05 PM   #260
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it is this detail which makes me think the cut out model is from a K-5. It looks differently in a K-7. The AF module is pretty large indeed.
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09-22-2010, 02:19 PM   #261
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perhaps i'm missing something but phase autofocus is used with t he mirror down - but the autofcus optics seem to be behind the mirror - how on earth do they work?
09-22-2010, 02:27 PM   #262
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QuoteOriginally posted by stormcloud Quote
perhaps i'm missing something but phase autofocus is used with t he mirror down - but the autofcus optics seem to be behind the mirror - how on earth do they work?
There's a smaller sub-mirror on the back of the large reflex mirror, which is partly transparent. So some of the light is reflected into the AF module in the bottom while the most light is going into the large prism finder. The viewfinder itself has nothing to do with the focusing (not even the ground glass screen unless you use it for manual focusing).
09-22-2010, 02:28 PM   #263
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Stormcloud: The main mirror is slightly translucent. Behind it is another, smaller mirror at an angle, directing the light down onto the AF sensor assembly.

09-22-2010, 02:28 PM   #264
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QuoteOriginally posted by stormcloud Quote
perhaps i'm missing something but phase autofocus is used with t he mirror down - but the autofcus optics seem to be behind the mirror - how on earth do they work?
The reflex mirror is partially silvered -- some light passes through the reflex mirror to a secondary mirror behind, where it is redirected to the AF sensor module.

This picture shows an example:

http://graphics.stanford.edu/courses/cs178-10/applets/slr-light-paths.jpg

Edit: Wow, beaten to the post by not one, but two folks. Well done, guys! ;-)
09-22-2010, 02:29 PM   #265
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QuoteOriginally posted by falconeye Quote
it is this detail which makes me think the cut out model is from a K-5. It looks differently in a K-7. The AF module is pretty large indeed.
Falk, here are two photos I found of the K-7 cutaway, and that detail looks the same (still doesn't not mean that the cut out is not a K-5, in fact the optics in the AF system look different to me):


09-22-2010, 02:31 PM   #266
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QuoteOriginally posted by stormcloud Quote
perhaps i'm missing something but phase autofocus is used with t he mirror down - but the autofcus optics seem to be behind the mirror - how on earth do they work?
The main mirror is semitransparent (Sony's marketing is using the wrong term: translucent means something else) for the AF secondary mirror to see anything. It's not a Sony invention So, the AF get's less light to start with (and additionally uses only a fraction of light in its lght path), adding to my argument that contrast AF will eventually outperform phase AF.

Here is the 100% crop out of the K-5 AF module, for easier reference:
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09-22-2010, 02:43 PM   #267
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QuoteOriginally posted by macTak Quote
Falk, here are two photos I found of the K-7 cutaway, and that detail looks the same (still doesn't not mean that the cut out is not a K-5, in fact the optics in the AF system look different to me):
Thanks for the photo.
The detail is different actually. Look at my attachment, left K-5 (from above), right K-7 (from your photo).

The K-7 "AF stray light blade" is a rounded thingy with a gap, the K-5's is straight meeting at a 90 angle.

So, the cut out model is from a K-5 confirmed. Moreover, the lens cut out is normally glued and cannot be removed. So, it cannot be the identical model. Of course, could still be from a K-7 which is why we need to look at that detail.
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09-22-2010, 02:48 PM   #268
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QuoteOriginally posted by falconeye Quote
Thanks for the photo.
The detail is different actually. Look at my attachment, left K-5 (from above), right K-7 (from your photo).

The K-7 "AF stray light blade" is a rounded thingy with a gap, the K-5's is straight meeting at a 90 angle.

So, the cut out model is from a K-5 confirmed. Moreover, the lens cut out is normally glued and cannot be removed. So, it cannot be the identical model. Of course, could still be from a K-7 which is why we need to look at that detail.
I thought you were talking about the top part of the "blade", now with your comparison crops it is indeed clear the bottom (part of the) blade is different, so it is confirmed
09-22-2010, 02:52 PM   #269
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QuoteOriginally posted by falconeye Quote
The shutter box has an absorber pad in the bottom.
Hi Falk,
Does this mean that PENTAX tries to adress the shutter blurr issue this way ? Could this be a solution according to your spontaneaous idea ?
09-22-2010, 03:40 PM   #270
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QuoteOriginally posted by bjan Quote
Hi Falk,
Does this mean that PENTAX tries to adress the shutter blurr issue this way ?
I don't normally imply anything if I state facts. I just noticed the absorber pad in the bottom of the shutter box. In the shutter blur study, we had to make wild guesses about a hard stop of the shutter blades or not. So, I thought it is an interesting detail to note.

Now, for the implications, it would depend if it is any different with the K-7. Unfortunately, the photo made from the K-7 cut out model lack the sufficient quality to tell. At least I am not able to say if there is the absorber pad or not.

If anybody has a better photo or better eyes ...
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