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Forum: Digital Processing, Software, and Printing
12-06-2009, 09:57 AM
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Could anyone point me in the direction of information on the structure of a Pentax pef file.
The first thing I can't understand is just how big the file is. I own an IstDS i.e. (3008x2008) sensor size. In my naive world that should give me a file size of 3008x2008 = 6,040,064 bytes + metadata. I get a file size of 10,793,974 bytes and I don't believe the metadata occupies over 4 Mb of space.
Also in the metadata there are a number of offsets and I presume one of them refers to the offset to the start of image data. Question is, which one.
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Forum: Troubleshooting and Beginner Help
09-30-2009, 02:28 PM
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Thanks to everyone who replied to this post.
To summarise -
a) Don't go above 400 ASA
b) Make a preference for RAW
c) There is a question mark on the lens quality. However I came across -
Pentax *ist DS Review Samples Gallery: Digital Photography Review These have been taken with a DA 18-55 and if I could get that I'd be a happy bunny.
d) There does not appear to be a problem.
e) I wonder what lens wildlifephotog was using.
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Forum: Troubleshooting and Beginner Help
09-22-2009, 02:00 PM
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Many thanks for your replies.
Apologies for that. It's like trying to see the impossible.
I enclose 3 crops from a 100% image. Same questions apply.
No post-processing software has been used. Images are straight off the memory card.
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Forum: Troubleshooting and Beginner Help
09-22-2009, 10:42 AM
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Last April I purchased a second-hand istDs via ebay as a replacement for a Canon A610 point and shoot. To cut a long story short I have always had mixed feelings about the istDs image quality and it is definition that I am most concerned about. I inherited a dirty sensor from the previous owner and had to have it professionally cleaned.
I enclose 3 images and would ask people to comment on the questions which follow. Images 1 & 2 were taken with the kit 18-55mm DA lens. I've had to cut the size down to 800x600 so it can be a little hard to tell.
Image 1 – The tell-tale problems are in things like the lettering on the ferry. ‘calmac’ is against a white background and the line between the letter and the background should be sharp. Instead it is slightly blurred/blotchy causing the loss of crispness. This applies to many of the things in the photograph, the people etc. Also the number plate on the car should be clearly visible.
Image 2 – taken in relatively low light. The result is blotchy, particularly the reddish flower in the centre.
Image 3 – similar to image 2 but taken with the Canon point & shoot. I think this image is better.
1) General comments on image quality.
2) Do you think there is a problem or am I expecting too much from the camera. Previous to the Canon I had a Pentax KM which was used for 30 years, say no more on image quality !!! This may have spoilt me.
3) If you think I have a problem with the camera what do you think it is and how might I rectify it.
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