The Pentax 645 will appeal mainly to DSLR or 35mm SLR shooters. The 645’s shooting experience is similar, the price of entry is very reasonable, and the results can be amazing for anyone just getting into medium format. Sure, a Lomography Diana is way cheaper (and admittedly a whole bunch of lo-fi fun), but for a camera you can grow into and actually use in a professional setting, the Pentax 645 is your best option.

Spec Summary

Name and film formats: The camera produces negatives that measure 6 centimeters by 4.5 centimeters, hence the name: the Pentax 645. The camera can shoot 120 film (the most common today), 220 film (much less common), and 70mm film (not at all common now). You’ll get 15 shots from a roll of 120.

Dates: Introduced June 1984 and eventually replaced by the Pentax 645n in 1997, a commendable 13-year run. So any 645 you buy today could be as old as Metallica’s thrash masterpiece Ride the Lightning or as new as Radiohead’s groundbreaking OK Computer…which is still pretty damn old, especially for a camera. Like those albums, the Pentax 645 is still totally worth adding to your collection. 

Current cost and availability: Six years ago, I paid $168 for the body, grip, and caps from KEH. A 120 film insert was $62 from the awesome used section at Roberts Camera, and a 75mm lens cost me $50 from some fellow on eBay. So all together, a complete kit in excellent shape set me back only $280. Today, the same kit could cost as much as $350 to $400, which is still an amazing bargain. Although the 645 is not as ubiquitous as Pentax’s 35mm K1000, deals definitely abound for patient buyers: you won’t have to hunt for long if you want one in good shape at a price that makes your wallet happy.

Autofocus: Nope, the 645 is a manual focus camera. If you want autofocus, pick up either the 645n or 645nii and an autofocusing lens. Those autofocusing models, however, will definitely cost much more.

Lens mount: Pentax’s 645 A mount. There are a bunch of lens options available at really good prices now, especially if you stick to the manual-focus series, the “SMC Pentax-A 645.” The great thing is that you can use those lenses on Pentax’s other medium-format 645 cameras if you decide to upgrade, even digital cameras like the 645D and 645Z. 

Batteries: 6 AAs in the grip. It’s awesome that such a cheap and readily available battery is used, but they do make the camera heavier.

Weight: And speaking of heavy, yeah, the Pentax 645 is a proper chunky monkey. The body, grip, and film insert weigh 46.2 ounces or 1,309 grams or 2.88 pounds according to the manual. But with batteries and a standard 75mm f/2.8 lens added, the kit tops out at 3.8 pounds according to my scale. That’s still not impossibly heavy of course (just about the same weight as Canon’s 1DX Mark III with battery and a 50mm f/1.4 lens), but the Pentax’s large, boxy, and bulky body magnifies the overall chunk factor. If Canon’s 1D series is a sleek sports car, Pentax’s 645 is a lumbering cargo van. 

Light meter: Yes, it has one—a classic center-weighted pattern that produces nice exposures. It works in all the main shooting modes the camera offers: program, aperture priority, shutter priority, and manual. 

Max shutter speed: 1/1000. That max speed is pretty typical of film cameras from the ‘70s and ‘80s, but it’s quite slow compared to digital cameras today. If you are shooting in bright light with fast film, you probably won’t be able to shoot wide open. In manual mode, the shutter speed can be adjusted in whole stops only. There is something refreshingly simple about being limited to whole stops, but for serious work on slide film, you’ll likely get annoyed.

Flash sync speed: 1/60. Very slow by today’s standards. 

Film advance and rewind: Both are automatic and pretty quick for an ‘80s camera. The downside is that both are also very loud, so you won’t be able to sneak any street shots. 

Continuous shooting: Yes, but the 645 is not a speed demon by any means. It shoots a mere 1.5 frames a second in continuous mode. Frankly, I hadn’t tried it until I started putting this review together, and I wish I hadn’t even bothered. It’s ultimately a nightmare of noise and wastefulness. For anyone shooting landscapes or portraits (which you probably are if you are interested in this camera), just save your film.

User manual: Like all film cameras, the Pentax 645 has a number of idiosyncrasies and old-timey irritations waiting for the uninitiated. I’ll go through some of them here, but grab a PDF of the manual from Butkus when you want an even deeper dive into the camera.


Tons of people started their film photography journey with a Pentax K1000 (even Drew Barrymore rocks one), but digital shooting over the past couple of decades has been dominated by Canon, Sony, Fuji, and Nikon—companies that have shaped contemporary photography with oftentimes bold and innovate gear. Pre-2000s, Pentax produced some pretty revolutionary stuff too. When the 645 camera appeared in 1984, for example, Pentax was attempting to create a new market at the intersection of image quality, automation, and affordability.

I mean, check out this particularly voluminous ad.

“One of a new kind,” Pentax insisted, but perhaps the better slogan would have been, “The best of all possible worlds.” Want great images? The 645 offers medium-format excellence. Need a camera that is easy to shoot? The 645 boasts motor-driven film advance and rewind as well as the autoexposure abilities of your dad’s 35mm camera. Don’t have a ton of cash? The 645 is way cheaper than any Hasselblad.

Even sports shooters were encouraged to get in on the goodness.

These days, shooting sports with the 645’s meager 1.5 frames a second prob seems a nonstarter, but medium-format magic combined with some still-modern conveniences? Yes, please. Take my money.

Just How Big Is the Pentax 645?

Really big. It might be the hugest huge you have ever seen in a handheld camera. Here is what the 645 looks like next to a regular old 35mm SLR.

Pentax 645 camera next to a 35mm camera
Pentax 645 lens mount and mirror compared to 35mm camera

As you can see from the pic above, the lens mount and mirror are gigantic. The area is substantially larger than 35mm film or full-frame digital sensors. It’s also larger than most modern medium-format digital sensors (e.g., Fuji’s GFX series or Pentax’s 645d and 645z). 

The increased bulk and heft, however, are totally worth it if you also want giant and luscious negatives. Here is a size comparison between a strip of medium format and 35mm negatives.

Medium format film strip and a 35mm film strip

The Grip and Batteries

If you are coming from shooting with a modern DSLR, you’ll appreciate the 645’s grip. It’ll likely be bigger than you are used to (the running theme of the entire camera), but it offers familiar handling and a great shooting experience. 

The grip includes the on-off switch as well as the shutter button. The grip is removable, but I’m not sure why you’d want to take it off: the camera won’t turn on or fire without it. Perhaps you might want to remove it for storage or transport, but it’s probably easier and more efficient to just get a bigger camera bag.

The little slidey switch thing that releases the battery compartment is a total pain to open (at least on my copy of the camera). It feels perpetually stuck or jammed. If yours is the same, don’t fear giving it a proper push to get it open. Mine hasn’t broken yet.

Battery compartment release tab of Pentax 645 camera

For batteries, I use Eneloop rechargeables and haven’t had a problem. Eneloops rock. Even if you aren’t interested in the 645 but do use speedlights with other cameras, check them out. They cost more, but last a good long while.

One bummer with the 645—and all old-school film cameras that I’m aware of—is the absence of a battery meter. It’s one of the few modern touches that I really miss. I mean, how much juice is left? It’s annoying to have them die in the middle of a shoot. The batteries are rated for a large number of rolls, so it’s never actually happened. But I’m paranoid. I always keep a fresh set in my bag just in case.

Finally, there is the “reserve” battery—a CR1220—located at the bottom of the camera. It’s behind the round cover with the two little holes. 

Pentax 645 reserve battery cover

In theory, the reserve battery is supposed to maintain some of the camera settings only in case the grip batteries die, but when my CR1220 finally gave up the ghost, the camera’s shot counter went nuts even though the grip batteries were still fresh. Not sure what happened, but apparently a working CR1220 is indeed important.

If/when your CR1220 dies, the manual says to send the 645 to Pentax for service, but that seems kind of crazy for a 40-year-old camera. I’m not sure Pentax would even take it. Instead, you can replace the battery by removing the cover with a pair of tweezers. 

The cover turns counterclockwise. I’ve read on forums that some are difficult to open, so you might have to give it some finger muscle. Mine turns easy-peasy.

Each battery is rated to last 5 years, so this CR1220 5-pack will get you through pretty much an entire career of shooting with the camera.

Film Inserts and Loading Film

Unlike most every 35mm camera, the Pentax 645 uses film inserts that you first have to remove from the camera and then load with film. Here is the back of the 645 with the insert in place and then the insert itself removed and with no film.

These inserts are not swappable mid-roll (like with Hasselblad’s mightily awesome camera system). Once you’ve loaded an insert with film, you have to shoot the entire roll before removing it. That is a bummer for sure, but you can’t have it all at the Pentax’s wallet-friendly price point. The 120 inserts can run close to $100 each now, and each will give you only 15 or 16 shots. 220 film inserts are still pretty easy to find and are less expensive these days, but the rolls cost more to develop and scan if you aren’t doing it yourself.

The first time I loaded film in an insert, I was a total fumbling idiot. It’s not actually hard to do, but it does take some getting used to. So no worries if it ends up a mess for you too.

To begin, get your film out of the wrapper.

Then insert the roll on the side with the red S on the spool retainer.

Grab the film leader and stretch the film across the insert. Make sure the black side of the film is facing up. If you see paper instead, you’ve put the roll in the wrong way. Thread the leader through one of the slots in the spool.

Tighten up the film by rotating the silver wheel thingy shown in the pic here.

Keep rotating until the Start arrows align with the red S and the red line.

You are now ready to pop the insert back into the camera.

Eyecups and the Viewfinder

The standard eyecup is large and hard and weird. I’ll link to a pic of one from KEH because mine has disappeared, long ago stuffed into a forgotten gig bag with other unloved bits and bobs. The eyecup is the consistency of a hockey puck. I’m not even sure what it’s supposed to do. Block light? Deflect bullets? Whatever the case, I just couldn’t get on with it.

Pentax 645 third-party eyecup

Instead, I acquired the cheap version pictured above from Amazon [update 2021: damn, the price has increased quite a bit in five years]. It’s bendy and comfortable, but you do have to remove it when you are loading/unloading film. Mine doesn’t fit as tightly as the OEM eyecup, so be careful if you are walking around with the camera on a strap or holding it at your hip. I’ve had my eyecup pop off several times.

There is also a “standard” eye cup available. It’s much smaller than either of the previous two. My camera did not come with one, but I would def like to try it. You can still buy them new from eBay sellers, like this dude, in Japan mostly.

It seems like a lot of secondhand 645s are missing eyecups. No clue why, but you’ll definitely want to get something. The bare edge is brutal on glasses and would be absolutely catastrophic on your eye.

Like the rest of the camera, the viewfinder is enormous. Some people feel that it is too dim, but with the standard 75mm f/2.8 lens attached, the viewfinder is just fine for me. Not beautifully bright by any means, but you shan’t feel like Hellen Keller looking through it. Slower lenses will be even darker of course.

Lenses and Crop Factors

75mm lens for a Pentax 645 camera

Pentax’s original A-mount lenses for the 645 are mechanically fantastic—super solid construction, butter smooth focus throw, and clicky aperture rings. Optically they are good too, but there is nothing faster than f/2.8.

If you grew up on 35mm film or full-frame sensors like I did, the focal lengths for medium format lenses might be mystifying at first. Multiply by 0.62 to get a 35mm equivalent. Because math sucks, here is a handy table.

Pentax 645 Lens35mm Equivalent
35mm21mm (21.7mm actual)
45mm28mm (27.9mm actual)
55mm35mm (34.1mm actual)
75mm45mm (46.5mm actual)
120mm75mm (74.4mm actual)
150mm90mm (93mm actual)
200mm125mm (124mm actual)
300mm180mm (186mm actual)
400mm250mm (248mm actual)

The really good news is that the old, manual-focusing 645 lenses will also work just fine on Pentax’s new digital medium-format cameras. The sensors though are actually smaller than traditional medium-format film, so multiply by 0.79 for a 35mm equivalent. Because math still sucks, here is another handy table.

Pentax 645 Lens (on a digital body)35mm Equivalent
35mm28mm (27.65mm actual)
45mm35mm (35.55mm actual)
55mm45mm (43.45mm actual)
75mm60mm (59.25mm actual)
120mm90mm (94.8mm actual)
150mm120mm (118.5mm actual)
200mm160mm (158mm actual)
300mm250mm (237mm actual)
400mm300mm (316mm actual)


Thank’s so much for your clear explications what is the use of the small wheel on the left side of the 645 with a white “s” and a red “c “..just below the” mode … “tool ?? Sincèrement AlPhilGe NS CAN

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