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07-09-2011, 06:42 AM   #16
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QuoteOriginally posted by Emacs Quote
You're wrong. The resolution is everything for landscapes. The lack of AA filter is the win here. Although D3X sensor has wider DR, the 645D's CCD has better linearity and tonal reproduction.
If resolution is "everything" then why did you cite DR, and tonal performances?

Also, the IR RAW samples from both systems doesn't support the claim that the 645D has better tonal reproduction than the D3x. If anything they are virtually indistinguishable other than a very slight bump in resolution. And even that is subjective(very close).

Though there's no discounting the lack of the AA filter on the 645D(terrible aliasing) which isn't an even trade-off if/when it comes-up as far as I'm concerned. And so as a landscape and studio shooter, I choose the D3x on this fact alone.

Then again... that's just me

07-09-2011, 07:17 AM   #17
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QuoteOriginally posted by Makten Quote
An interesting and often forgotten question is the ability to separate the subject from the background. The fact that the fastest lenses for Pentax 645D is only f/2.8 (f/2.4 if you use the P67 105 mm) on a cropped sensor, makes it even more interesting to compare to let's say a simple 50/1.4 on the D3X. Stop it down to f/2.2 and you've got the same DOF and probably a very good bokeh. Can that be matched by the Pentax lenses wide open, or do you have to stop them down as well? What does the bokeh look like?

The "crop factor" between 24x36 and 33x44 is only 1.27, so there's a lot to be had with f/1.4 lenses on the smaller format. The step from 33x44 to 6x4.5 (56x41.5 mm) is the same; 1.27, which makes up better for the "slow" lenses.
Please take a look at Zeiss -- Depth of Field and Bokeh, in particular the section "The big format comparison" where is a table showing equivalent f-numbers for various format cameras. From that table, the equivalent f-numbers for identical DOF of 35mm and 6x4.5 formats are f/1.4 and f/2.4 respectively.
07-09-2011, 08:17 AM   #18
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QuoteOriginally posted by Emacs Quote
40mp resolution is enough to avoid moire in most cases.
And I told you not to be a fanboy, now you behave exactly like those stupids who's shouting about K-5 IQ. Larger sensor, better feeling overall. Simple.
Actually there is moire(visible moire) in the IR still studio scene with the 645D which I found to be rather disappointing. And that's okay given that its just an example. Though it does stand-out against the competition given that it was not an invoked situation;


Taken from ACR, without sharpening, PP etc. - ie. sharpening amplifies.

Therefore, in this particular example, the D3x holds a considerable advantage in both texture and final IQ due to moire respectively.

-

Having said that... the second portion of your post(personal attacks) is both unwarranted and unacceptable.

Last edited by JohnBee; 07-09-2011 at 08:23 AM.
07-09-2011, 08:29 AM   #19
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QuoteOriginally posted by JohnBee Quote
Actually there is moire(visible moire) in the IR still studio scene with the 645D which I found to be rather disappointing. And that's okay given that its just an example. Though it does stand-out against the competition given that it was not an invoked situation;

Therefore, in this particular example, the D3x holds a considerable advantage in both texture and final IQ due to moire respectively.

Having said that... the second portion of your post(personal attacks) is both unwarranted and unacceptable.
So, I admit the D3x is better tool for shooting bottles, trash cans, etc
But how such regular patterns refer to landscapes?
They usually find out the lack of AA is an advantage of 645D for landscapes. You are the first one who tell the opposite.

07-09-2011, 08:30 AM   #20
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QuoteOriginally posted by Makten Quote
Sorry, but that example says nothing. .....
Not quite nothing, it told me exactly what I wanted, i.e. use of the 90mm for portraits ( the gnome is perhaps larger than you realize and so not such close focus). I was also concerned with the ability to manual focus the lens. You can certainly crop your film scans to a 33x44mm FOV to determine exactly how the specfic images that interest you would appear using a 645D.
07-09-2011, 08:40 AM   #21
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QuoteOriginally posted by rhodopsin Quote
Please take a look at Zeiss -- Depth of Field and Bokeh, in particular the section "The big format comparison" where is a table showing equivalent f-numbers for various format cameras. From that table, the equivalent f-numbers for identical DOF of 35mm and 6x4.5 formats are f/1.4 and f/2.4 respectively.
If course, you don't need any tables for that. Just have a look at the sensor area. The 645D has NOT got 6x4.5 format, so f/2.8 on the 645D is equivalent to f/2.2 on 24x36, as I stated. If you want to reverse it, f/1.4 on 24x36 is equivalent to f/1.8 on the 645D, and no such lens exists.
07-09-2011, 08:42 AM   #22
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QuoteOriginally posted by Emacs Quote
But how such regular patterns refer to landscapes?
They usually find out the lack of AA is an advantage of 645D for landscapes. You are the first one who tell the opposite.
I suppose this depends on the type of landscape shooting were talking about. However, I've encountered moire in areas such as; fencing, cloth or weave(netting, sails etc), feathers, wires or rope or posts and various other linear geometry.

And I'm sure there are other areas where moire becomes an issue, but I didn't shoot long with a sensor which did this.
However I wouldn't overlook the fact that I based my observations on studio work also, which I think made a very appealing market for MF type photography. And again... though moire can be addressed, if you've ever had to work with it, you may remember that it can be a real pain in the a** to work around.
07-09-2011, 10:32 AM   #23
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QuoteOriginally posted by luftfluss Quote
it's kind of a cropped MF (44mm x 33mm) whereas MF sensor is usually 48mm x 36mm.
Unlike the Phase/Leaf 40/30MP backs, Hasselblad 40MP, and Leica S2 which all (about) the same size--the Leica is a tad smaller.

07-09-2011, 10:46 AM   #24
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I think you should convert images from both to the same resolution (say 16mp) and give us 100% crops of many situations under the same subject-lighting conditions-settings.
07-09-2011, 10:59 AM   #25
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Forgot to answer this...

QuoteOriginally posted by Thomas Quote
Not quite nothing, it told me exactly what I wanted, i.e. use of the 90mm for portraits ( the gnome is perhaps larger than you realize and so not such close focus). I was also concerned with the ability to manual focus the lens. You can certainly crop your film scans to a 33x44mm FOV to determine exactly how the specfic images that interest you would appear using a 645D.
I hope I didn't seem to harsh with that statement. Didn't mean anything bad.

What I meant is that short DOF, or rather blurred background, seldom is a problem (in the sense that you want it) at fairly close distances. I even find portraits with say an 85 mm lens on 24x36 to give too shallow DOF at larger apertures than f/2.8-4 or so.
Perhaps I'm interested in a different style concerning short DOF than most other photographers, but when I want a blurred background, it's at larger distances or with wide lenses.

Then of course a larger format with slower lenses give a different look, because of the better correction of the lenses. But in this case I wonder if the difference is large enough for someone like me. I'm actually not considering this camera, but I'm still very interested in what you can achieve with it.
07-09-2011, 11:24 AM   #26
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I could have sworn I subscribed to this thread- but I guess not! Sorry for taking so long to reply.

QuoteOriginally posted by hcc Quote
- It is not just about bodies but also lenses. A real comparative review should try to get comparable-quality lenses, and not just the 'kit' lenses. For example, I would love to see a series of comparison with different types of primes for example. This might include/encompass third-party lenses.
We're going to be comparing them with the Nikon 35mm F1.4 G AF-S on the D3x and various lenses on the 645, including the A 35mm F3.5, FA 45mm F2.8, A 55mm F2.8, and FA 45-85mm zoom. For standalone tests, we're also bringing the A 120mm F2.8 macro and the FA 400mm 5.6 tele.

Our discussion as far as lenses go is going to be focusing more on what's out there. The bottom line is that availability in general is currently an issue for owners of both bodies.

I regret to say that we weren't able to acquire either of the new DFA lenses, although there has recently been a very in-depth user review of the 25mm,

QuoteOriginally posted by hcc Quote
- Could the review include some specific type of shootings? Like landscape, sports, BIF, portrait? For example I love to shoot some dynamic motion and actions. I rarely see some real-world comparison (incl. percentage of keepers).
Due to limited time with the D3x, the comparison will be limited to landscape and close-ups, but we'll try to squeeze in portraits with the 645D. If you're looking for a pro body for sports, then the D3x or D3s will serve the purpose much better than the 645D- it's much more of a studio/landscape camera, although it does make up for its poor AF system in other areas.

QuoteOriginally posted by hcc Quote
- Can the review discuss backward compatibiity? This is a great asset of the K-series bodies.
One thing that has already impressed us is that the 645D is fully backwards-compatible with all 645 A series, 645 FA series, meaning that all shooting modes are supported. As an added bonus, you can use the aperture ring, and lens distortion correction is available for FA lenses. The 645D can also use all 67 lenses (with adapter) in Av or M modes, with no stop-down metering required.

Of course, given the fact that there are currently only two modern lenses for the 645D, this was more or less to be expected.

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07-09-2011, 11:26 AM   #27
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QuoteOriginally posted by Makten Quote
An interesting and often forgotten question is the ability to separate the subject from the background. The fact that the fastest lenses for Pentax 645D is only f/2.8 (f/2.4 if you use the P67 105 mm) on a cropped sensor, makes it even more interesting to compare to let's say a simple 50/1.4 on the D3X. Stop it down to f/2.2 and you've got the same DOF and probably a very good bokeh. Can that be matched by the Pentax lenses wide open, or do you have to stop them down as well? What does the bokeh look like? The "crop factor" between 24x36 and 33x44 is only 1.27, so there's a lot to be had with f/1.4 lenses on the smaller format. The step from 33x44 to 6x4.5 (56x41.5 mm) is the same; 1.27, which makes up better for the "slow" lenses.
This is certainly worth testing- but I don't think adapting K-mount lenses onto the 645 would accomplish much in a practical setting.

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07-09-2011, 11:57 AM   #28
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It is a pitty that you only have one lens for D3x, a nice portraitlens would be great. But then again, it is what it is.
07-09-2011, 02:12 PM   #29
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If the purpose of this test is to determine the best image quality, I'll make this simple. I've owned both. My primary work is architecture and the 645D is superior to the D3x, especially in sharpness. But, let's be fair, they are two different beasts entirely. The 645D is slow to work with, thumbnails take about 5 seconds to pop up. The D3x has live view, something that should have been on the 645D, as well as a vertical release. Otherwise, I think the ergonomics of the 645D have the edge on the D3x. Better placement and reasonable size of the buttons give the 645D the edge for me. The 645D also has horizontal level and vertical plumb display on the LCD, the D3x has only the horizon. For architecture, the 645D is clearly at advantage. That said, the Nikon has the older PC and PC-E lenses, the Pentax has none. I'm awaiting the arrival of the 45MM Hartblei Super rotator to see if it is a viable alternative.

Next to the glass. I use both current and thirty year old glass on the D3x. As I am not a tech geek and wouldn't know an MTF from a BLT, I look for real world performance. Some are better than others in both new and old and I suppose the same can be said for the 645D. I have the 45-85, 75, 35, 120 and 150, none of them built specifically for the 645D and everything I have shot so far with them has been very satisfying.

Since acquiring the 645D I have sold my D3x (business isn't good enough to keep both) and held onto the D3s with my arsenal of PC and PC-E lenses. So far it was the right decision for me. I hope this helps.
07-09-2011, 03:30 PM   #30
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QuoteOriginally posted by Makten Quote
Forgot to answer this...


I hope I didn't seem to harsh with that statement. Didn't mean anything bad.

.
No offense taken

Here's one that's more like your example. Not a BMW, oops Alpha, but a John Deere . Taken with a 67 90mm @f/2.8. Same for the second shot.



Last edited by Thomas; 07-09-2011 at 04:51 PM.
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