My Pentax 645z Medium Format Conversion in a Nutshell

Last month I bought a Pentax 645z medium format digital camera from a 72 year old Arizona photographer who had purchased it from B&H photo last December and had only shot 1200 frames on the thing. What follows is a somewhat disorganized brain dump of everything I’ve learned so far.

Grand Canyon — Pentax 645z with 45–85mm/4.5


Some people are scared by the idea of medium format cameras. They’re big, heavy, expensive, slow. The backhoe of the photographic world. And while all of those things are true to some degree, they’re not really as bad as people say. The body is about the same weight as a 1Dx or Nikon D5 and about the same price. It shoots three frames a second, which is more than I ever need shooting portraits. Big? Well this one is relative. It’s visually imposing compared to smaller cameras, but that’s actually one of the things I like about it. Pull this thing out of your case and the subject sits up straight and gets engaged in a way they don’t when the camera is the one they themselves have at home. A reason to buy one? Perhaps not, but it’s a not insignificant factor. Don’t forget the other big difference between this and your average smaller camera and that is the ratio of the frame. While most smaller formats are 3:2, the Pentax’s sensor is 4:3. more of a squat rectangle that’s closer to a square. This suits me just fine as I’ve come to the habit of cropping my pictures to 5:4 anyway.

Pentax 645z with 45–85mm f/4.5 lens

The camera does feel great in the hands though and the engineers at Pentax are very certainly photographers themselves as the controls are much more logically laid out than the were in my long experience with Canon bodies. For instance there is a little rotary switch right on the side of the mirror box that activates mirror lock-up. No going and digging through 4 layers of menus to find the setting while your hands are freezing at the top of the mountain in Yosemite.

The menu system isn’t the greatest. The fonts are big, and navigating is simple, but I still don’t have a handle on where I go to find the setting I’m looking for without flipping through options for a minute and a half. Luckily you don’t really need to dig in there very often since the physical controls are so good.

Some people will tell you that to get the best out of a camera like this it’ll have to live on a tripod. I’ve been both hand holding and using it on a tripod for the past 6 weeks and think both are valid. Sure, if you’re handholding at 1/50th of a second because that’s all the light you’ve got (remember, the fastest lenses are f/2.8, and most are f/3.5 or f/4.5), well then yes you might smear across some of the fifty million pixels due to camera shake, but A) that’s part of the fun and B) if you’re using strobes, this isn’t a problem at all.

Speaking to the auto focus. It’s more than fine for my usage with the older FA lenses that I have, but it is certainly not high-speed in comparison to a modern high-end SLR. The AF points are clustered very close to the center of the frame, but I’m a center point and recompose kind of guy, so that’s not really an issue for me. That said, with the shallow depth of field inherent on a larger sensor with relatively fast lenses there are some instances where the plane of focus with stray when you recompose. You’ve got to use your eyes and adjust by moving an inch or two forward or back. None of this is terribly different from f/1.2 or f/1.4 lenses on a 35mm sensor, but worth noting.

This is my first camera with a rear screen which can tilt up to perpendicular and down a bit to help when it’s on a high tripod mount. This along with live view mode allows you to use the rear screen as a sort of waist level viewfinder. There’s even focus peaking which you can turn on so that you don’t need to be zooming in and out to check focus. I’ve used this feature a couple of times with mixed results, cropping to square in post. I’m a fan of cameras with waist level finders so perhaps I need to dedicate some more time to this variation on the theme. The idea of using this camera like my old Hasselblad 500 is very appealing. The one thing it’s missing is a feature to mask the screen in live view to square. Actually make that two features as the screen only pivots in one dimension and can’t be flipped up for the same usage in portrait orientation which is my preferred way of shooting. Can’t have everything I guess. At least the viewfinder is pretty great.

In the nitpicking category I’ll say that I don’t like the way the shutter feels or sounds. This is purely an irrational cosmetic concern of course and one which I’ll learn to live with. I’m a fan of a very fast feeling shutter, either a crack/pop or nearly silent ‘snip’ kind. Mechanical and sure. The mirror in the Pentax however is big and dampened to reduce shake when you’re using it handheld so it sounds a little like your grandfather is in there firing it by hand. Still gets 3 frames a second though so it can’t be that slow. Just my perception.

The battery life has been nothing short of excellent. For the years I shot Canon 1D and 5D bodies I rarely thought about whether my battery had enough juice in it. I just assumed that it did. Sure, I’d put it on the charger the night before a big shoot just to be sure, but it never failed me. Granted, I’m the kind of guy who will take 120 pictures of a subject for a magazine shoot as opposed to the 1200 that some people do. I don’t think I’ve ever used burst mode on any camera I’ve ever owned. That said, I took the 645z on a 8 day vacation to the American southwest last month with two fully charged batteries and no charger, and I didn’t need the second battery. I shot about 300 pictures on the trip and the battery gauge was still showing full bars on the flight home and that was with a fair amount of review back in the room at night. Pretty extraordinary for a medium format camera. I’d also like to point out that it’s one battery, as opposed to one for the body and one for the back with the more modular systems. I should also point out that extra batteries are a common and inexpensive type that you can buy on Amazon. Aftermarket brands are 2 for $25, even from Pentax they’ll only set you back $50.

Ellen Tamaki — Pentax 645z with 45–85mm f/4.5 lens


One of the big advantages of this system is the fact that Pentax has been making 645 cameras with the same mount since 1984, which means that there is a relative glut of used glass on the market. Not every single design is amazing, but some of them are stellar and worthy of comparison to the best that Hasselblad and Schneider have to offer. I’ve even seen a technical analysis which compares the 35mm designs from each company giving the crown to the Pentax. That’s the thing about lenses. Within a format the designs are fairly standard across manufacturers. The math and design was all worked out decades ago. For example a Canon 50/1.4 and a Nikon 50/1.4 will have similar if not identical design and characteristics. Really only differing in casing and coating. Certain focal lengths are simple and accurate designs within a format. On 35mm it’s the 50mm and 100mm. On 645 it is the 75/80mm, 120 Macro, among others.

Because the Pentax 645 format has been around a while there a few different lines of lenses that will work on the 645z. The oldest are the A series from the 80’s and discontinued, they’re manual focus and are so-called because they have an aperture ring with an Automatic setting. Next are the FA lenses which are auto-focus as well as auto aperture, most of these were released in the 90’s, but are still in the current lineup. They use a screw based autofocus, that is certainly noisier than the nearly silent ultrasonic motors used in modern 35mm designs but they’re accurate and optically superb. Finally are the handful of DA and DFA lenses released in the past few years. These use a modern silent motors and are weather sealed, with prices to match.

I spent a lot of time doing research on the forums and review sites and have started my lens collection slowly. First I needed a bread and butter lens for my normal work. On my 35mm system I was a 35 and 50mm kind of guy. I owned an 85/1.2 ‘portrait’ lens but 80% of my shots in the past couple of years were on the 35 and 50. So I bought a used FA 45–85/4.5 zoom. With the conversion factor of .79 (the magic number to figure out the 35mm equivalent focal length with this guy) that leaves me with a zoom of 35–67mm zoom. Right where I need it to be for my work. It’s not the fastest zoom, but my god is it optically great. List price is $2200 at B&H. I found mine used in ‘budget’ condition at KEH for $340. Yes you read that right. Does it feel brand new? Not quite. The zoom ring is a little inconsistent in its rotation, but the images that come out of it are consistently great. Sharp across the frame, focuses accurately and fast. For the record, the ‘budget’ rating of used gear at KEH is equal to ‘Good’ or better elsewhere and I’ve made a number of great finds there.

My next purchase was something outside my comfort zone. A long old school portrait lens. And when I say old school I mean that I bought a manual focus A series copy of the 150mm f/3.5 prime. It’s got a built-in lens hood, is built like a WWII tank, and is surgically sharp. Almost to a fault. I’ll admit that I haven’t quite gotten my mind around this guy. 150mm on the Z is the equivalent of 120mm on 35, so it’s a fair bit longer than any I normally use. The manual focus is creamy smooth and slows me down in a good way. This is not a run and gun camera for me anyway. The only real problem with it is that the closest focusing distance is about 3.5ft, which is fine for a true headshot with minimal cropping, but obviously not ideal if you’d like to go even tighter. At only $135 in immaculate condition though, it’s a no brainer. What I will likely do in the future is to purchase a copy of the 120mm macro, which is an amazing focal length for this format. A bit shorter than the 150mm and with the ability to close focus. The similar Hasselblad version has almost cult status in the portrait world. They go for about $900 used. I’ve got my eye out.

The last lens I needed to round out my kit was something to replace my beloved 28mm prime from the old system. This is the lens that I rely on most for my more cinematic conceptual images. My Canon 28/1.8 was my desert island lens. In fact I think I’m going to keep the lens even though I have no camera to put it on. It’s got that much nostalgia wrapped up in it. The Pentax equivalent is an FA 35mm f/3.5. I found one on KEH had had a 25% off coupon so it was about $750 in excellent condition. New ones are $1600 so again, I got a steal. I’ve only used this guy once so far and require more testing, but it seems optically more than up to the 50 megapixels I throw at it.

A couple other quick takes. Adorama had a used FA 75mm/2.8 which I bought for $300. It’s a tiny screw focus lens, basically the ‘normal’ lens of the film based 645 system, but I think something was wrong with my copy as it would have a hard time focusing. Hunting from one end to the other and grinding while doing it, so I took it back. Pictures I made with it before sending it back were technically amazing though, albeit a little bit long for my taste. They make what is sort of the new normal kit lens for the system, the new DFA 55mm/2.8. Which is silent and weatherproof, to the point where there are videos of a guy pouring sand on top of it at the beach and then taking the whole camera/lens combination and running it under the shower to clean it off. Insane. It’s a bit expensive new, but I think I’m going to end up getting one as my walk around lens when I only want to carry one and the zoom is too big and heavy. Had my eye on one for about $600 earlier today.

Sunrise in Monument Valley panorama — Pentax 645Z with 45–85mm/4.5

Speaking of great deals, while I was on KEH buying the 35mm a couple of weeks ago, they had an HPRC hard waterproof rolling case with custom foam inserts for the 645z for sale. Like new condition. Normally this case is only available as part of a $16,000 kit that Pentax sells that includes the body with three of their most modern and expensive lenses. With the coupon I got it for about $90, which is insane. The case alone costs $160 new not to mention the custom inserts and happens to fit my kit almost perfectly.

Before I wrap up the lens section, it seems as good a time as any to bring up arguably the main limitation with the Pentax vs the big boys and that’s the lack of leaf shutter lenses and the relatively slow sync speed of 1/125th of a second. Personally I’ve lived with 1/180th as my sync speed on my Canon for a very long time and never found it to be a major limitation. Short DOF shots with a strobe while outside on a sunny day is just not a scenario that I find myself in very often. And if I did I would have a number of options to deal with it. 1) I could just go and rent a Hasselblad for the once every few years I need that feature, 2) I could use ND filters to knock down ambient and then just make up the difference in flash power, or 3) I could buy one of the two manual leaf shutter lenses that Pentax made for the format back in the day and I hear work just fine. Not really an issue for me. Certainly worth the price difference many many times over.

Kelsey Gangnath — Pentax 645z with 45–85mm/4.5


Up until very recently, I was a dyed in the wool Lightroom user and still think it’s great software, but in the process of getting used to these new files I did some serious tests to find the best tools to get the most out the files and have settled on Capture One for the moment. I’ve never been a particularly huge fan of C1, though I know there are plenty of you out there. With my Canon files, it never seemed to have much of a lead on the renderings that I was getting out of Lightroom. Plus, the way my mind works, the catalog modality always made more sense versus the way sessions work. Before you say anything, the catalog functionality that C1 added a couple of years ago is not the same thing. It’s ok, I’ll adapt.

The problem is that in the latest version Phase One has artificially blocked DNG files from the 645z from showing up in C1. Apparently it worked in version 8 from what I understand and then they shut off of the faucet in version 9. The 645z and the Phase One IQ250 share a similar if not identical Sony sensor, however the Pentax costs $7k where the Phase costs $38k or something so I can understand their fear of being undercut. This is a pretty adolescent way to maintaining market share in my opinion, so I have no moral scruples about what I’m about to tell you next.

I’m cheating. Well, not cheating exactly, but I’m certainly pulling the old switcheroo. I’ve created an Applescript recipe which uses an cross-platform open source command line app called ExifTool so change the metadata of my Pentax 645z files to make Capture One think that they are Phase One IQ250 files. And you know what? It works great. C1 applies the delightful color profiles they’ve worked out for their camera and since it’s the same damn sensor, they look perfect. Far better than I’ve been able to get in Lightroom, even with a fair bit of twiddling. All of the data is there, but somehow the Lightroom profiles for this camera, including some I’ve made myself, tend to look sickly and off. I could keep fighting, but if there is a better option elsewhere, I’m fine going there. I still need Lightroom for tethering and will use it for printing and generally organizing my portfolios and such, so it’s not like it’s being banned from my applications folder. I’ve also found that when using Lightroom’s little trick of merging RAW files into a RAW panorama, the resultant RAW panorama file can be opened in C1 as well which makes the dream of 120MP landscapes a pretty simple reality.

My old workflow involved extensive processing in Photoshop after my time with the RAW files in Lightroom, but I’ve found myself trying or needing to do less to the images overall and doing most of it in C1 with Photoshop. I’m able to do this partly because of the tools in C1, but I give most of the credit to the sheer quality of the images. The files really are something. We’ll get to that in a minute.

There is one weird thing I’ve observed that I haven’t quite figured out yet. On my Canon cameras, if I shot with strobes the WB set to a custom 5600k and then opened up the RAW file in Lightroom, the WB would be set to 5600k and the colors would be right in the ballpark except for a slight shift due to a modifier that warmed or cooled things a bit. However with the 645z, if I set the white balance manually to 5000k, the same file shows up ‘as shot’ in Lightroom at 6400k and C1 at 4800k. Both visually similar. This makes no sense to me. First, why would the WB that shows up in the RAW conversion software differ from the one I set in camera. Secondly, why would it differ so wildly in different directions and yet still look ‘correct’. The 4800k in C1 should be far too cool with a 5600k strobe and the 6500k that Lightroom shows up as should be way too warm. It’s all very confusing. And it’s not just my copy of the camera. I had used a Ricoh loaner and a rental before and both exhibited the same thing. I’ve done some searches and come up with nothing. Kinda makes me feel insane. That said, if I know how to get accurate and true color out of it, then it’s not much more than a curiosity. If anyone has any thoughts on this or happens to know the engineers at Ricoh please let me know. I’d love to get to the bottom of it.

As a little aside, I’ve found a few features that I prefer in either C1 or Lightroom. For instance, the color rendering and profiles are amazing in C1 and I like the straightening tool. However the overall organization, lens profile correction (Lightroom includes ones for my 45–85mm zoom for instance) and the way the highlight and shadows sliders work (The ones in C1 can easily look cartoony if overused), I give the crown to Lightroom. Really I wish I could merge the best of each into a single super app.

Molly Coogan — Pentax 645z with 45–85mm/4.5

Image Quality

Finally we get to the real reason I’ve done all of the above and spent all the money. Image quality. As you might have expected, I think it’s stellar and I’m not just saying that. If you get all the normal technical stuff right the files just sing. Color, depth, sharpness, etc. All as good as I’ve seen. And holy crap is there a lot of dynamic range in the DNG files that come out of this thing. Coming from my Canon, it’s at least a couple of stops better, and even then when you pull the shadows up and I mean four or even 5 stops, there’s no visible noise. Particularly at low-iso settings. Just picture data down there in the blackness that you didn’t know was there until you pulled it out. Really extraordinary stuff.

Here’s a quick example of my buddy Cisco ringed by lens flare. Left is the RAW file out of camera. As you can see, drastically underexposed. On the right is the same pushed 2.5 stops and the shadow slider opened up a bit.

Francisco Underexposed — Pentax 645z

I’ve actually had to retool my process and learn to trust in my camera a bit more. Knowing that if the shadows look a little dark on rear screen that there is plenty of information in there I can work with when I get home that I didn’t have on my old system. My friend Klaus Enrique has one of these cameras as well and was one of the people who talked me into it. His big thing was the lack of what he refers to as ‘jaggies’. Everything just seems smooth and sharp at the same time. Nothing breaks up in that digital way you might be used to. They really do feel like drum scans of really great medium or even large format film images. I’m not going to say that I’ll never want more pixels to work with, but at the moment, I don’t really know what I’d do with them. This sensor is certainly pretty far up the curve of diminishing returns. Just don’t forget to load up your computer with RAM and try to work on your images straight from an SSD.

Beyond the depth of color and shadows is the shear amount of pixels and their quality. Here’s an un-retouched crop of Molly’s eye from the picture above.

Molly Coogan (inset)

Come on. Who could want or need much more than that.

I have learned a couple of things about the way Pentax has tuned their implementation of the sensor. I’ve found that in usually digital fashion you should expose to the right to maximize the information you’re recording into the most significant bits, but especially with this camera, DON’T blow the highlights. My advice is when in doubt, underexpose. Highlights recover fine, probably in line with what you’re used to with smaller sensors or a bit better, but it’s nowhere near the information you can pull out of the shadows.


Overall I’m very happy I took the plunge. The body was expensive, but not drastically different than a pro-level 35mm body, and image quality bang for the buck it just knocks it out of the park. Lens availability is great if you do your research and know what to get. In fact the lens kit I’m putting together for this guy is far cheaper than the old kit for my Canon. I won’t be carrying this thing around the city on my neck anytime soon, but that’s not what I got it for, and I’m not the type of photographer who carries a camera everywhere I go anyway. For travel and stuff I’ll probably pick up a Fuji x100 when the new 24MP version comes out. Or maybe pick up a used x100T at that point. Between that and my phone I’ve got walk-around covered. For everything else I’ll pull out the big guy.

I’m sure there are things that I’ve missed and passages that need clarification. If you have any questions, be sure to leave them below and I’ll do my best to answer them.