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06-27-2008, 10:15 PM   #1
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Messing about with the K20D sensor

Thought I'd see what the K20D sensor might be capable of so I used it as a sort of "digital zoom".

1. First pic is just an overall 1:1 shot taken with the kit lens zoomed to 32mm just to give an overall view as it might appear to the naked eye. The red frame is the aprox full frame view taken with a 500mm scope at 15x. Distance to target was aprox 550 feet.

2. Full frame view taken with a 500mm scope at 15x at highest and largest jpg format (14.6mp at **** quality level)

3. 100 percent crop of #2 at 6mp (same as my old DL)

4. 100 percent crop of #2 at 2mp

5. Pics 2, 3, and 4 were all resized to 800x534 px to conform to posting rules and posted here as compressed jpgs.

6. Just a 100 percent close crop from frame number 2.

I know the methodology leaves much to be desired but still it does give some idea of what the sensor is capable of.


Last edited by wildman; 08-30-2008 at 02:44 PM.
06-28-2008, 02:51 AM   #2
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My K20D is definately faulty in the focusing department then I could not get anywhere near that sort of quality at your cropping ratios even at 14.6mp and premium quality. I have suspected it was faulty for a while but things like this prove it.
06-28-2008, 03:00 AM   #3
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Great measurabation and pixel peeping! Keep up the good works!!
06-28-2008, 04:55 PM   #4
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QuoteOriginally posted by RiceHigh Quote
Great measurabation and pixel peeping! Keep up the good works!!


Now that's funny! Glad you have a sense of humor about this, RH!

06-28-2008, 04:59 PM   #5
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I'll play. I posted this a few months back when I went to the Shuttle launch without my Bigma (doh!). I wanted to see what the K20D and DA*50-135 could do in an extreme crop situation.

First, here's a small version of the complete picture.



Next, here's a 100% crop of just the Shuttle on the pad.



Proper processing could make this even better, but I'll take it for a webshot.
06-29-2008, 08:30 AM   #6
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QuoteOriginally posted by wildman Quote
Funny you should say this. I am not sure my K20D focus is right on the money either.
Because all of my shooting is of wildlife with scopes (always manual focus) I'm not sure the focus is as good as my DL. To put it simply so far the K20D does not do as well as the the old DL.

I'd like to hear more about your (and other's) focus issues.

This is typical of what I get on the DL. I have not done as well with the K20D so far...
Those are very impressive. What scope do you use?
06-29-2008, 10:19 AM   #7
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QuoteOriginally posted by PENTAX K Quote
Those are very impressive. What scope do you use?
Depends on the situation:

Pentax 80mm ED spotter
Astro Tech 80mm f/7/560mm APO triplet
Pentax 100mm ED spotter
Celestron 102mm f/5/500mm "Wide View" achro
Orion 120mm f/8.3/1000mm achro
07-25-2008, 06:43 AM   #8
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Wildman I was wondering why that is with extreme magnification shots. I have a *istD and a K10D. I've never really tested them against each other on the same subject but sometimes the *istd seems to nail a shot much better than the K10D even though i think I got the k10D shot right.

Beautiful bird shots Btw

07-25-2008, 07:37 AM   #9
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I think some of you are confused, go back and re read his first post. The pictures are not crops from the first picture, but crops from the second picture!
07-25-2008, 08:04 AM   #10
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I get that. it's a reference shot.
07-25-2008, 11:51 AM   #11
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QuoteOriginally posted by wildman Quote
Depends on the situation:

Pentax 80mm ED spotter
Astro Tech 80mm f/7/560mm APO triplet
Pentax 100mm ED spotter
Celestron 102mm f/5/500mm "Wide View" achro
Orion 120mm f/8.3/1000mm achro
Wildman, how do you hook the spotter to the camera? do they have the mount for it? I was looking at the PENTAX PF-65ED II, then I don't seem to able to find information how to hook it up with K10D... sorry for the newbie question.
07-26-2008, 02:28 AM   #12
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Hi,

could you post a crop of the red square for reference. It would be nice to see what the kitlens produced.

Jan Rinze.
07-26-2008, 03:17 AM   #13
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QuoteOriginally posted by wildman Quote
I know the methodology leaves much to be desired but still it does give some idea of what the sensor is capable of.
The only way of getting an idea of what the sensor is capable of without specialist equipment, is to compare it with another sensor, using the same lens.

It would be really excellent, if anyone has, for instance,

- a *istD
- a K100D
- a K10D
- and a K20D,

- and one of the better lenses

, and could take some (as far as possible identical) pictures with each for comparison, also taking all possible measures to ensure accurate focus and elimination of camera shake.

Then, assuming the lens itself had adequate resolving power, we could look at the 100% crops, and see actual differences in detail between what the different sensors could record.

Of course, the different processing that each camera does with what comes off the sensor means that all other things apart from the lens are not quite equal, but it would be a start.
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