Comparison of Sensor Specs - 645D Against Others

(Image Source Page: http://www.pentax.jp/japan/products/645d/feature.html)

Since the 645D was announced, people, in particular Pentaxians, have been arguing about the advantages against the shortcomings of the new 645D when it is compared against other DSLRs of different sensor sizes, pixel counts and form factors. I think it would be of no harm for me to list out the factual data of some of the sensors used by some of the current popular DSLRs that could be compared, for an overview on the basic physical and specification differences, before heat debates and more discussions are to be carried on..

Camera / Digital Back	Sensor Size (in mm)	Sensor Area (in mm^2)	Resolution	Aspect Ratio	Total Mega Pixels	Pixel Size (in um)	ISO Range
Pentax 645D	44 x 33	1452	7264 x 5440	4 : 3	40.24	6.1 x 6.1	200 - 1000 (100 - 1600 Expanded)
Mamiya DM40	44 x 33	1452	7350 x 5562	4 : 3	40.88	6.0 x 5.9	80 - 800
Mamiya DM56	56 x 36	2016	9288 x 6000	3.1 : 2	55.73	6.0 x 6.0	80 - 800
Mamiya DM33	48 x 36	1728	6726 x 5040	4 : 3	33.90	7.1 x 7.1	50 - 800
Canon EOS 1D3 / 5D2	36 x 24	864	5616 x 3744	3 : 2	21.03	6.4 x 6.4	1D3: 100 - 1600 (50 - 3200 Expanded) 5D2: 100 - 6400 (50 - 25600 Expanded)
Nikon D3X	36 x 24	864	6048 x 4032	3 : 2	24.39	6.0 x 6.0	100 - 1600
Nikon D3S / D700	36 x 24	864	4256 x 2832	3 : 2	12.05	8.5 x 8.5	D3S: 200 - 12800 (100 - 102400 Expanded) D700: 200 - 6400 (100 - 25600 Expanded)
Pentax K-x	24 x 16	384	4288 x 2848	3 : 2	12.21	5.6 x 5.6	200 - 6400 (100 - 12800 Expanded)

So, for anyone who is interested to compare, now you can compare all these parameters and calculate their ratios and differences in percentage and etc.

Do it endlessly till the end of the days, which is just another kind of measurbation! ;-D Enjoy!

645D Samples at Pentax Japanese Website

Well, it says that it is under construction, but particular clever Pentaxians did have discovered their existence and links!

There are eight downsized photos, in 1743 x 1306 pixels only, uploaded at the following links:-

http://www.camera-pentax.jp/645d/photo/0X.jpg, where X = 1 to 8

There is no EXIF data of any contained in the downsized photos, though.

I have linked directly to the original "large" pictures with my above thumbnails, just click on any of the thumbnails above will download the larger image, a new tab/window will be opened.

For the samples, I've found that the resolution and dynamic range are good, the 3d feel is superb! But however, I am totally not impressed with the colour response and skin tone(s) as shown, which is just not my cup of tea anyway! :-(

K-x' DxO Mark is Out (And My Last Prediction is Correct!)

See:-

http://www.dxomark.com/index.php/eng/Image-Quality-Database/Pentax/Kx

As I predicted last time (in December 2009), the DxO Mark for the K-x would be very close to that of the Nikon D90 and D5000 and yet once again I am correct! :-)

Nevertheless, the K-x performs really well for an APS-C cropped DSLR. It is ranked at 19 for all DSLRs tested so far. Well, even it is not the best APS-C, it is already very close to the Nikons and actually the difference is almost negligible. (As for the K-7, the results are just pathetic, in contrast.)

645D Announced!

Full Specifications etc. are now officially online!

http://www.pentax.jp/japan/imaging/digital/medium/645d/spec.html
(in Japanese)

Update: An English Spec can be found at the DPR:-
http://www.dpreview.com/news/1003/10031002pentax645d.asp#specs

And, the "kit" prime lens is here:-

http://www.pentax.jp/english/news/2010/201007.html
(in English)

Sample photos have not yet been uploaded, though.

100% Bingo! I Derived Exactly Correctly for the 645D Actual Sensor Size!

One year ago, I made my calculations and guessed on the 645D sensor size. Some people did disagree much at my Blog and also elsewhere on the net, but now it is proven today that I did guess right and correctly for the exact figures, 100% correct! =Victory= :-D

Just see the official announcement that has just been published:-

http://www.camera-pentax.jp/new/news05/index.html (645D Product Preview News Vol. 5)

Quoted, "新製品では44×33mm大型CCDセンサーを搭載。35ミリ判とは世界が違う描写を実現するPENTAX 645D。"

Well, even Pentax reps at the last year's Japanese PIE said that they could not tell at that point, which I also reported.

So, anyway, let's simply wait for this "4433D" (which this name I gave to the 645D one year ago!), there is only one day to come!


Last News: A Little Bit More Update on the 645D (Official)

RiceHigh's Subjective Ratings on Pentax AF Lenses on Pentax DSLRs 2010

http://ricehigh.atspace.com/RiceHighs_Subjective_Ratings_on_Pentax_Lenses_on_Pentax_DSLRs_II.html
(A Separate Tab/Window will be opened)

Enjoy! Take mine as plenty grains of salt as everything are totally subjective according to my own practical experiences and impressions! YMMV!

Well, the Quality Variations that may exist could surprise you, especially for Pentax lenses that were produced after 2003! On the other hand, putting aside such annoying quality issues, I do find that Pentax have been improving their lens design silently over time, even for the "same" lens model (but for times and so many times they just couldn't control properly the quality! E.g., just look at the DAL lenses' case, and maybe also the DA 16-45 copies that I had and have as well!).

As a final remark, I haven't rated "Focusing Accuracy" in my summary as I found that focusing accuracy depends much more on the body than on lenses, generally speaking (although particular Pentax lens models are still more vulnerable to focusing errors, e.g., the FA 31 Limited). So, I'd just better leave this out in my table.

Update (3-9): More fields are added for performance aspects and lens production information are also added.


Recent Related Articles:-

Standard Zoom Mega Shootout! (DA Vs FAJ Vs DAL Vs SA Vs FA!)

Useful Lens Review Links

K-x Debug Mode Tutorial - AF Adjustment

Standard Zoom Mega Shootout! (DA Vs FAJ Vs DAL Vs SA Vs FA!)

Test Methodology and Conditions:-

1. K-x on Tripod, Single AF mode, Central Single AF point selected, 2 second Timer with MLU;

2. Focal Lengths were tested as marked on the lenses, Av Exposure mode (and of course), Matrix Metering, No Exposure Compensation;

3. Portrait Custom Image -1, 0, 0, 0, Sharpness 0, AWB;

4. All images are resized to 3,999 pixels in width and no other re-touching is made to the images, All EXIF data preserved. Click Any of the Thumbnails will download the Large Size Image in a New Tab/Window. (Note: All Large Files!)

Lens & Focal	f/4 or 4.5	f/5.6	f/8
DA 16-45 @16
DA 16-45 @20
DA 16-45 @28
DA 16-45 @35
DA 16-45 @45
FAJ 18-35 @18
FAJ 18-35 @24
FAJ 18-35 @28
FAJ 18-35 @35	Not Available
DAL 18-55 @18
DAL 18-55 @24
DAL 18-55 @35
DAL 18-55 @45	Not Available
DAL 18-55 @55	Not Available
SA 18-55 @18
SA 18-55 @24
SA 18-55 @35
SA 18-55 @45	Not Available
SA 18-55 @55	Not Available
FA 24-90 @24
FA 24-90 @28
FA 24-90 @35
FA 24-90 @50
FA 24-90 @70
FA 24-90 @90

How to Measurbate, then? Download the Large Files and inspect the image centre and borders, note about contrast and sharpness, colour differences, distortion of the images and so on. Compare against one and each other(s) for the same/near focal length and see the effect of different apertures on the output Image Quality.

I do not test f/11 for all lenses as it is almost for sure that f/11 will not be as sharp as the diffraction limit is usually reached for APS-C DSLRs. My advice is that if you want to stop down, usually don't go beyond f/9.5 for optimal image quality! And, dust specks, if any, are more visible from f/11 and onwards, too.

Well, which lens(es) do I like more or most? Umm.., I think putting aside the different range and the physical characteristics of them (e.g., size and weight, design and operation, etc.), I would rate: FA 24-90 > DA 16-45 > FAJ 18-35 > SA 18-55 ~ DAL 18-55, as long as IQ is concerned, overall speaking.

Interestingly, according to Bojidar Dimitrov's K-mount Page, the optical formulae of the DAL 18-55 is the same as that of the DA 18-55II, whilst my "Samsung" Blue Ring SA 18-55 is the same as the original Pentax DA 18-55. So, my this comparison should show what are the actual difference(s) between the two optical formulae on the Image Quality, if any. But do bear in mind about sample variation as well for those cheapo kit lenses (of which the QC is not really good from my experiences).

What do you think, on the other hand? :-)


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Lens Matching with My Navy K-x