Signal Mtn

In Search of the Unicorn

A Review of the Pentax 645D - part 2
From Blizzard to Desert

by Miles Hecker


Almost 100% of my photography is done outdoors. I spend a great of time in the mountains of Wyoming, my home state. Any photo gear I use must be capable of commonly functioning in inclement weather and at temperatures down to 10°F. I have shot in temps as low as -20°F. Conventional digital MF gear just won't do this.

The Hasselblad H3 and H4 series are rated down to 32°F and have no weather sealing. I have a friend in Utah who sold his H3D because it just didn't function at 18°F. Hasselblads response was basically it's not supposed to, end of story.

The Pentax 645D is billed as completely dust and weather sealed. It is also billed as having cold resistant performance and a -10°C temperature rating. That's 14° for us English unit types. How did it stack up in real life?

The answer was very well. On a late January trip to photograph Yosemite in winter, David Brookover and I got a room at Yosemite Lodge and waited for an incoming storm. Sometime during the night of our second day there, it arrived. The next day we woke up to a foot of fresh snow and a blizzard in progress.

Tunnel View Blizzard

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Tunnel View Pano

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We headed up to Tunnel View, set up, and stood out in the snow, waiting for it to break. We were out in the worst possible conditions, melting heavy wet snow, humidity near 100%. I kept my hand over my 45-85mm lens when the snow really intensified, when things went to a white out, I covered the lens with a plastic grocery bag. We were out there for over 3 hours. When we started, there were seven of us die hard's. At the end, only three cameras were still shooting. My 645D, David's Nikon D3x and another shooters Nikon D3S had keep going throughout it all. Four other photographers whose camera brand shall remain nameless, quit with fogged up viewfinders or lenses.

In the cold, I've shot the 645D down to 10°F for extended periods with no problems. A Canadian friend has shot his down to -6°F for several hours at a stretch. He did have to swap out the cold battery several times. A Pentax K10D has been used on sounding balloons and seems to work to temps well below 0°F. See this link.

Focusing in The Field

The 645D has Pentax's' latest 11-Point SAFOX IX+ auto focus system. It has been one of the most accurate auto focus systems I've used, at least on static objects. I won't be using the 645D to shoot running pronghorns in the near future.

I normally use only the center focus point and then I recompose if need be. The SAFOX IX system seems to work well from macro distance out to infinity. For 98% of my shots it has been spot on. The 2% it was off on, were by the slimmest of margins. Easily correctable with a bit more USM. My 5Dmk2's center focus point occasionally misses critical focus at macro and short distances, but works well at long distance. My 7D's focus system works well at all distances. I also shoot the Pentax lenses at their sweet spot which is about f11. This will hide small focusing errors, but for me at least the results are quite good. The performance in short is on a par with modern 35mm SLR's and quite a bit better than the dated AF systems used in most other MF cameras.

Manual focus, if your eyes are 20/20, is also quite good. The viewfinder is bright, 98% accurate and the diopter correction is quite good. I have a Pentax MF 80-160mm zoom which I have used with excellent results on the 645D. If your eyes are old and astigmatic I am afraid you'll have to stick with AF lenses.

Oak Trees

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False Kiva

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Dynamic Range and Noise

In March I headed off to the high desert of SE Utah to give the 645D a workout under drier and warmer conditions. I met Colorado photographer Danny Oldfield and we spent a week shooting in the desert.

Shots I've taken on that trip to Canyonlands, along with shots from Yosemite have left me very impressed with the 645D's dynamic range. In Yosemite I shot alongside David with his D3x. The D3x has been the king of the dynamic range hill in the 35mm game. After close examination of real world photos with ACR RAW conversion thrown in, the 645D matches it stop for stop. DxO tests show the D3x being a stop better, but this is direct sensor only measurement of the RAW files. On real photos I find it a dead heat.

The Canon 5Dmk2 comes up short here. In the shot a left, we had a large range of lighting between bright skies, direct sun and full shade. The 645D held the range from darkest shade to brightest sky with a single exposure. The two fellows shooting 5Dmk2's next to me required a split ND filter or multiple exposures to grab the whole scene. If they held the sky, there shadows crunched badly. If they exposed for the shadows the sky would blow out. I suspect they could have recovered the skies in RAW conversion, but don't know for sure.

That said, the use of a soft split ND filter could have solved their problem. I use one with my 5Dmk2 much of the time. Techniques we learned shooting film with 7 stop dynamic range, work very well for a digital camera with "only" an 11.9 stop dynamic range. We don't all need cameras with 13.5 stop dynamic range. The 5dmk2 is still a bargain at $2500, if you use it properly. It just can't compete dynamic range wise with cameras in the $7000-$10,000 price range.


The 645D has a 77 segment multi mode metering system. It has matrix, center weighted, and spot metering modes. I tend to use matrix in most settings and spot metering in tricky light, especially snow scenes.

In good light, the 645D's matrix metering is all but infallible. If anything, the 645D has a slight tendency to underexposure, but only in dimly lit, overcast conditions. So watch your histogram in dimly lit scenes.

Battery Life

I would rate the 645's battery life at between 400-600 shots. It really didn't seem to change much at temperatures down to 10°F. I would suspect that use under Arctic like conditions would lower that figure considerably. That said, even fairly new batteries can fail. Always carry a spare battery!

Needle Sunrise

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Druid Arch

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The Prints

The Holy Grail of landscape photography is the making of large detailed prints. Ideally, this prints should make you feel you are one with mother earth. In the past that meant shooting with large or medium format film cameras. How does the 645D do in meeting that challenge? The current generation of full frame 35mm DSLR's had already set the bar pretty high, but the 645D pushes it higher still.

If the the biggest print you'll ever make is 16"x20", you can probably keep your 5Dmk2, D3x or A900 and be happy. At that size you'll be very hard pressed to see a great improvement in IQ from the 645D.

If you jump to a 24"x30" print the story is different. The 645D will produce prints I would rate A+, the little 35mm guys would yield B+ print quality. The differences would be in micro detail, micro contrast and especially tonality.

If you move up to 30"x40" print size, the difference would be dramatic. Much better micro detail, micro contrast and tonality in the 645D prints. Give it an A rating compared to a B- rating. The more extremely fine detail the print has the more obvious the difference will be.

In simple terms the 35mm full frame guys produce prints that equal the quality of 6x7 MF film cameras, the 645D produces prints that equal the quality of 4x5 LF film cameras. These mirror the conclusions made in the 2006 State of the Art Shootout done on the Luminous Landscape web site. That test used the first 39MP MF backs as the state of the art digital device. The big change is the 645D costs $9995, the backs used in that 2006 test, when added to a MF camera cost about $33,000. A similar MF system today would still cost close to $20,000.



I can say that the following Pentax 645 glass has performed very well in my testing. The 35mm, 75mm and 80-160mm zoom manual focus lenses are first rate. The 45-85mm zoom and 120mm macro auto focus lenses are also top notch. The 45mm prime is okay but not great. I have not yet shot my Hartblei 45mm T/S rotator. I find f11-f13 to be the sweet spot for these Pentax lenses.


In the three months I've shot my Pentax 645D it has performed superbly. It has proven to be a digital MF camera that can produce images that rival the quality of 4x5 large format film. It is capable of producing stunning 30"x40" and larger prints. It is fully weather proof and capable of meeting the field demands of diverse landscape photography environments. It is priced at a fairly reasonable $9995.

Hills Oak

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Back to Part 1

To see the results of a direct A-B field test with the Nikon D3x, click on this link.


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