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Pentax 645Z vs Alpa technical camera
- Thread starter voidshatter
- Start date
I have to say, there appears to be something a bit off with the Pentax 28-45mm performance here. I own this kit and have never seen it looking anywhere near as mushy as some of these at the edges. Mine is razor sharp right to the edges and corners. Sure, I'd expect a Rodenstock prime to beat it, but I'm not exaggerating when I say its the best zoom I have ever used by quite a margin. There can be some curvature at the long end, but I have thousands of pin sharp frames where the edges are all but indistinguishable from the centre. I literally haven't a single frame that looks as bad as some of those on display here. What the cause is I don't know, but I'd urge people considering the Pentax & 28-45mm not to take this comparison as indicative of performance. Mine does a fine impression of a Zeiss ZM or Leica prime on my Leica M, only at 51MP. I was simply staggered when I ran the first tests to ensure it was well-centred.
For ultimate performance, great primes and lots of MP is always going to win, but there are many reasons to prefer one system over the other.
For ultimate performance, great primes and lots of MP is always going to win, but there are many reasons to prefer one system over the other.
voidshatter
Member
I agree with you that the 28-45 sample I tested may be de-centered a bit, as I have also seen others posting razor sharp corners of that lens. However, if you look into the official website of Pentax, you would find similar test results of soft corners. I can only conclude that there could be some variance between samples, or possibly the field curvature is more severe when you focus close.
Link to the sample image at Pentax's official website
100% crop of bottom right corner:
GrahamWelland
Subscriber & Workshop Member
One over the other? Sorry, I just don't understand ... What is this 'over' or 'or' word?? There is no 'or' on this forum, just 'and' :ROTFL:
Ken/Don, how am I doing?
Btw, that Pentax GAS in a box looks excellent at B&H. I could see them selling those easily.
Bryan Stephens
Workshop Member
I know.. I am seriously eyeing that kit.... Ugh. Dante.... is that you?
GrahamWelland
Subscriber & Workshop Member
Bryan, you know that you want, no, need it!
If if I weren't so embedded into Phase One gear I'd seriously consider the Pentax as the grown up DSLR. Just been shooting my DF+ again tonight and I seriously HATE the f'ing thing when it locks up. Great when it works but then it lulls you into a false sense of security and then WHAAM! Or rather ... Nothing.
Bryan Stephens
Workshop Member
I know that feeling. Last time it happened to me was in the spring when I was on a long weekend shoot, and I only had the DF+ with me (I wanted to travel light....If if I weren't so embedded into Phase One gear I'd seriously consider the Pentax as the grown up DSLR. Just been shooting my DF+ again tonight and I seriously HATE the f'ing thing when it locks up. Great when it works but then it lulls you into a false sense of security and then WHAAM! Or rather ... Nothing.
) , and it kept locking up to the point where the entire weekend was not enjoyable and my images suffered because I was so on edge. A month later, I no longer owned the DF or the lenses.The main reason for using a MFD tech cam is usually lens movements, but of course people would be disappointed if it didn't have top notch lens performance, it's after all supposed to be the successor of large format film.
I think it's interesting with these "sanity check" comparisons.
It would be nice to test against some mid-range tech cam gear too. If you get say a second hand H3DII-50, smack it on a F-Universalis and a Kapture Group sliding back, and use some Schneider Digitar glass the cost is similar to a new Pentax 645z.
Alpa, Rodenstock and Phase One is probably the most expensive choice you can make.
I think it's interesting with these "sanity check" comparisons.
It would be nice to test against some mid-range tech cam gear too. If you get say a second hand H3DII-50, smack it on a F-Universalis and a Kapture Group sliding back, and use some Schneider Digitar glass the cost is similar to a new Pentax 645z.
Alpa, Rodenstock and Phase One is probably the most expensive choice you can make.
Graham, along those lines, we cannot wait for you to start the thread on your replacement tech cam purchase....for starters, the 90HRW should be replaced with the 90HRSW
I have to agree with turtle, my version of the 28-45mm is never as soft as your examples. Perhaps there is some variation in samples of the lens. I note the Ricoh image you linked was taken at f/9 and the corner crop appears to be no more than a few feet from the lens; likely outside or near the DOF range.
A corner crop from my sample. Handheld at 1/125.
IMGP1787 copy by tsjanik47, on Flickrcorner crop:
Attachments
aztwang
Member
You know you want to do it Ken....Christmas is 1 month away!:thumbs:
voidshatter
Member
Still, for this official sample image (grabbed from Pentax official website) I find it hard to believe why Region A is inside DoF while Region B is outside DoF, if not for field curvature or soft corner (or bad copy).
At least without a side-by-side comparison against a technical camera, this looks good enough (if the noise is not due to over-sharpening).