Probably one of the better ways of comapring the Pentax K100D and the Nikon D40 is to read the reviews -
BUT pair the reviews by the same site and compare the reviews side-by-side ......
read not only the words, but compare carefully the sample images -
Here are the ones I found paired -
DCRP - I like this site because their reviews often are insightful -
DCRP Review: Pentax K100D
DCRP Review: Nikon D40
Imaging-Resource - detailed, comprehensive and well organized -
Pentax K100D Digital Camera - Full Review - The Imaging Resource!
Nikon D40 Digital Camera - Full Review - The Imaging Resource!
dpReview - another comprehensive and detailed review site
(but misses focus speed and shutter lag for dSLRs - why?) -
Pentax K100D Review: 1. Introduction: Digital Photography Review
Nikon D40 Review: 1. Introduction: Digital Photography Review
PopPhoto.com - site of "Popular Photography" - long established magazine -
covers some important aspects other "comprehensive" sites miss - like focus speed at different light levels -
Camera Test: Pentax K100D - - PopPhotoOctober 2006
Camera Test: Nikon D40 - - PopPhotoMarch 2007
OK my (biassed) opinion -
Pentax K100D -
- cheaper - by about $36 in kit form -
someone has posted that Pentax may be doing its rebate thing from 10/18(?) - see
Time to refresh the rebate.
- shake reduction built-in for all lenses - this is a really valuable feature - at least for me.
- compatible with all Pentax lenses - including the new (and expensive) SMD lenses - the focussing is with the mechanical screw-drive and not via the lens ultrasonic motor.
- good image quality
- low image noise, and quite acceptable even at ISO3200
- loud'ish mirror slap/shutter
- limited buffer for continuous shooting (4 frames for JPG and 3 for RAW)
- common AA batteries -
BUT very sensitive to batteries - have to use good high capacity NiMH or LSD like eneloops - or expensive lithium AA like Energizer e2 lithium.
Nikon D40 -
- good image quality - possibly "better" than K100D - but probably difficult to see in practice.
- low image noise - again possibly better than K100D - but read and see
Nikon D40 Review: 23. Compared to...: Digital Photography Review -
"The D40 delivers a clean looking image at both ISO 800 and 1600 which maintains its detail well, although not as detailed as the Pentax K100D images."
- limited compatibilty with older lenses - eg: no auto-focussing with non AF-S lenses.
- unlimited continuous shooting for JPGs; 6-7 for RAW
- quieter shutter.