Pentax 645D review

Discussion in 'Pentax' started by miles_hecker, Apr 9, 2011.

  1. Great review. Nice to see the vast difference between full frame and the 645D.
    I'll have to download the full size images and load them in faststone using the compare feature to really compare them. Still, I don't doubt the outcomes.
     
  2. Great job and fabulous example images too! Thanks for posting this!
     
  3. Miles (wow, you posted your review 5 separate times on photo.net!),
    Your information regarding the Hasselblad H3D in cold temperatures is very inaccurate. I regularly shoot in well below freezing temps with the H3D (and the H2 prior) without any failure. In fact, I did my ice fishermen series on frozen lakes and rivers exclusively with the H3DII39.
    I have plenty of other snow/ice photographs, obviously made in very inclement weather conditions. I have used the H2 in temps around -18F, sadly, I failed to function, not the H camera. I have worked with the H in temps as high as 114F, no issues.
    The 32 degree temp rating from Hasselblad is the Kodak sensor temp rating specified by Kodak.
    Please correct your otherwise good review and thank you for posting it. Be well.
    Kind regards,
    Derek Jecxz
     
  4. Miles, very cool test. I've been waiting for a 645D v. 5DMkII head-to-head.
    Derek, I'm glad that your experience with the Hasselblad has yielded good results in winter climates, but if the H3 and H4 are rated at 32F, that doesn't change anything. If they can withstand more, that's great! But ratings from the manufacturer are present for a reason. If someone else's H3 couldn't shoot in 18F, than for that photographer a change was needed. We all push our gear, but the rating gives us an idea as to what the unit should be able to do without a hitch. I don't think changing the information in the review is necessary.
     
  5. Jeremy,
    The ratings aren't failure ratings. For instance, the Pentax ist D was probably rated to 32F, and the K10D was rated to ??.. They all work in colder climates. My Samsung TL500 probably isn't rated for rime ice instantly freezing to it, then melting into the crevices later in the day, or sub zero weather, but it works in all of them! Heck, the pentax ist D with a 4mmx6mm chunck of plastic missing from it's top panel still works in snow and cold. Talk about refusal to fail.
    So probably both Derek and Miles are a bit wrong for comparing the meaningless ratings.
    I do like the image comparisons though, and I find the debate on luminous landscape funny to say the least. They are claiming the D3X is limited by Nikons crappy lenses! Ha, so there you have it. Nikon makes crappy lenses. Some people even note that they would prefer the test to be done with a Zeiss optics or Nikon PC prime lenses. Of course, before anyone blows a fuse, I'm speaking in sarcasm.
    I guess it find it funny, if you were to compare Pentax 35mm (type) lenses on the Nikon forum, I doubt anyone would say their lenses suck, but when faced with the 645D and existing 645 mount lenses, all of a sudden Nikon lenses aren't good enough. Which is it? Are they great lenses or are they junk? I think probably the 645D blows the D3X and the 5DII away because the sensor is significantly bigger and almost 2X the resolution. The lenses are a weak point in almost any high res system!
     
  6. Justin,

    Of course, you're right: Ratings aren't really a "Hey, don't do this or I'll quit working for you" types of numbers. But I do view it like overclocking a CPU. Sure, you can make your "rated" 2 GHz processor run at 4+ GHz, but at what cost? 3 months of life versus decades? That heat and stress is bound to shorten the life of the unit. I don't imagine Cameras being any different. I've used my *istDS down to 6F and it worked quite well: the LCD was slow, and the battery life was short, but those are side effects of the cold regardless of the device.
    <P>
    I'm not above seeing the ratings and then blasting through them anyway, but it is nice to know where the limit is so I can brag about it to you guys later. My wife is tired of listening to that stuff, so all ya'll are stuck with me.
     
  7. I don't know if the life of a camera is shortened by the cold. Humidity, maybe? Heat (mainly the sensor of a CMOS), maybe? Water, only if it gets inside the camera! Dust and sand are probably the factors that will kill cameras and lenses the fastest!
    I've been overclocking my phone for over 16 months straight, 1Ghz from 500Mhz, works flawlessly. You forget one thing about processors, a lot of them are designed to be overclocked. The TI OMAP 3 series was designed to work at a variety of clock speeds, and dynamically at that. I actually run mine at 250/1000 or 500/1000, unless I'm streaming media, then I run it at 600/1000. The lower speed is screen off, higher speed is screen on. The governor that controls the OC kernel is temperature regulated, so if the processor gets near the threshhold it will cut the OC to normal, if it gets above it than it shuts the phone down.
    BTW, I'm not claiming unregulated OCing doesn't cut the life of a processor, but my take is dynamic or screen state based OCing probably actually reduces strain on the processor over the long haul.It also increases battery life since the processor gets the work done faster but idles faster too!
    Back to the cold and a camera, if there were moving parts, I could see the cold killing the camera. It might freeze lubes and make moving parts stiff and increase stress on the winding system. But with digital I see no reason it would shorten the life.
    My guess is the temperature ratings are so people don't contact Pentax or Hassy with complaints that there screen got slow at 6F or that there batteries died on an important shoot in the cold.
    Common sense tells us (or at least those of us that deal with this weather every year) that extreme cold is bad for batteries and LCD performance. Though you ist DS should have no issues if you use Energizer Lithium AA batteries. Those are rated to -40C/F and are used by polar expeditions they are so effective in the cold.
    Honestly, the only issues I've ever had with my cameras in the cold is batteries. The OLED screen (on the TL500) worked perfectly (no lag) in 0F temps, but the batteries did die when I was using fill flash! put a warm battery in and the camera worked flawlessly again!
     
  8. I think probably the 645D blows the D3X and the 5DII away because the sensor is significantly bigger and almost 2X the resolution.​
    Technical point: 40Mpx is not double the resolution of 20Mpx. It's only 50% higher.
     
  9. Good point!
    I was talking in terms of MPs but I understand and am aware of the point you are making about resolution.
    But technically also the camera is capable of higher DR and larger photosites than it's FF competitors. Neither of which I mentioned.
    So the 50% greater resolution, the higher DR, and the larger photosites all probably play a small role in creating a better final file.
    Remember, on the informal Luminious Landscape write up, they actually thought the top of the line full frame Canon was broken because the files looked so poor compared to the two MF cameras they tested it against.
    If I'm making any point at all, it's gloating I was right. The difference between digital 645 and FF is much greater than digital FF and digital APS-C. Head to head test seem to show it to be true time and time again.
     

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