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Pentax 645
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Pentax 645

Pentax 645 with 75mm f/2.8. enlarge. You can find these used at these direct product links to Adorama and eBay. When you use these links to get yours, it helps me keep adding reviews of this old stuff. Thanks! Ken.


December 2008        more Pentax reviews



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Intro   Specs   Performance   Usage   Recommendations

The Pentax 645 is probably the biggest bargain going in medium format film cameras. I paid under $300 for this rig above, delivered, in December 2008. Back in 1997, B&H got $2,025 for this same 1outfit, new!

It replaces the old Yashicamat 124G, which was the biggest bargain in film days. Now that amateurs have abandoned film, these Pentax 645s are almost being given away.

The Pentax 645 has a built-in motor drive and all auto and manual exposure modes, as well as a full line of excellent lenses available cheap. For the same price as the Yashicamat, which used a no-longer available PX625 mercury cell, pop six AAs into the handle of the Pentax 645 and you're OK for over a hundred rolls of film.

It's easy to shoot digitally. Send your film to a lab like NCPS and have them scan it at the same time. I get 17MP (50MB) files back for just a few dollars.

This manual focus Pentax 645 was replaced by the autofocus Pentax 645N in 1997. Pentax added mirror lockup and called the replacement for the 645N the 645N II. The 645NII is still expensive, but even the AF 645N sells for just a few hundred dollars without lens.

This original 645 is very inexpensive because serious photographers who shoot these sorts of cameras prefer to have auto exposure lock and manual metering that reads to fractions of a stop, which this 645 doesn't do (the newer 645N does).

This is a skeleton review. It will be growing, but 90% of what you need to know is already here.

I'll cover all the faults, but know that the Pentax 645 is capable of very serious results, and that it's lots of fun to shoot. Set it to Pro (Program) mode, and just focus and press the button. I've never used any medium format camera that made it so easy to get such fantastic results.



This original 645 has three glowing inadequacies:

1.) No AE lock.

2.) Manual meter only reads to the nearest full stop.

3.) Exposure compensation only in full stops.

This Pentax 645 was designed for amateur wedding photographers, who of course shot negative film. They don't care about thirds of an f/stop, but we transparency shooters do.

This 645 makes very accurate exposures, but if you need to tweak them precisely, you do it by changing the ISO in third stops.

If you need to lock an exposure, you revert to manual mode and pray, because the manual meter only reads go full stops. You jiggle the aperture ring, and drop it into the middle click in the range over which the meter says OK

Hey, for $300 for a complete camera body, film magazine and lens, I can work around all of this.


Specifications with commentary      top

Intro   Specs   Performance   Usage   Recommendations


56 x 41.5mm, 15 or 30 exposures on 120 or 220 film.



You need different "inserts" for either 120 or 220, which sell used for under $50 each. When you buy a Pentax 645 setup, be sure you get one of these backs. They are not changeable mid-roll. Unlike a Hasselblad, you can't change film types except at the end of the roll. Then again, a new Hasselblad film magazine costs almost triple what I paid for the complete used Pentax 645 camera, lens and back you see above.

Pentax also made a 70mm magazine, in case you're taking your Pentax 645 on a Moon mission. Even if1 could get Velvia 50 in 70mm spools, I know of no lab which can run it without having to chop it into smaller strips.


Crop Factor


645 film has 2.6 times the area of full-frame 35mm.

In other words, a 100mm lens on 645 has about the same angle of view as a 60mm lens does on 35mm film.

Here's the chart:


35mm Equivalent



Huge, almost life-sized with 75mm lens, but dim. Dioptometric control. Split-image and microprism surrounded by ground glass. LEDs for shutter and aperture encroach on your composition in the lower right of the finder.



TTL, center-weighted.


Exposure Modes

All four: Program, Aperture, Shutter-preferred, and Manual.



Vertical cloth focal-plane, 1/1,000 to 15 seconds, bulb.


Cable Release

Standard, drilled into the shutter release button as God intended.



6-AA in the grip.

Good for over 100 rolls.


Performance      top

Intro   Specs   Performance   Usage   Recommendations

The first thing you notice is the huge finder. Then you notice how dim it is. The finder isn't fun: it's too big, too dim and too fuzzy. The fastest lens in the 645 system is f/2.8, and the finder is dim. Pop on an f/3.5 and its worse. I don't even want to think what it looks like with a teleconverter or slower lens.

The aperture and shutter speeds are displayed on a cut-out which obscures the lower-right of the finder. I didn't find this much of a bother.

The in-finder exposure compensation warnings are tiny, but that's OK since you're not likely to use them. You'll be tweaking the ISO, for which there is no warning. Beware.

Meter range runs down to 1 second wide-open at ISO 100, below which the display blinks while indicating slower exposures. At smaller apertures, it happily reads to slower times up to 15 seconds. I haven't tried to see if it will work well below its rated EV3 minimum for night shots, or if you'll want to use a Digisix external meter.

The Pentax 645 is a noisy thing, worse than a Canon 5D. There's a lot going on, so if you want to show up and look and sound like The Man, go for it. The Pentax 645 is great for cover shots, but not for covert shots.

This is 1984. LCD watches were replacing LED digital watches as what was cool for hackers. The top LCD comes from a 1984 digital watch, and so does the dim LCD illuminator.


Usage      top

Intro   Specs   Performance   Usage   Recommendations

Top, Pentax 645

Top, Pentax 645. enlarge.

Forget the user's manual. It's so poorly written that it's better to ignore it.

Film loading is obvious: twst the key on the back, pull it out and follow the arrows on the magazine. The start index is next to the supply spool.

Press MODE or ISO and UP-DOWN to adjust. Do the same for EV, which adjusts exposure compensation, but only in full stops.

It's easy to go from Program to Manual. For Program, the lens must be in A. Take the lens out of A, and you're in Manual exposure at the set aperture. Look for OK in the finder as you change exposure.

The ON-OFF switch is more of a shutter lock than a power-off switch

When you get your film back and look at the strips, each new frame lies above the previous one.

It's tough to turn on the meter if a cable release is threaded into the shutter release.

The film counter is semi-retarded: when your roll is done, it will read 16 (120) or 30 (220) and the Pentax 645 hangs up until you unload it. If you forget that you only get 15 shots on 120 (30 on 220), you might sit there cursing when the P645 stops responding to the shutter release.

As expected in 1984, LEDs in the finder were a luxury. Press the top LED button to turn them on and off to amaze your friends. The O button illuminates the top LCD the same way old LCD watches lit up.

On the light table, the images line up with newer images above the previous frame. This makes it weird for filing and for contact sheets.


Recommendations      top

Intro   Specs   Performance   Usage   Recommendations

The Pentax 645N is much better, with knobs for controls instead of up-down buttons, but hey, for about $300 complete, I'll have a blast shooting this.

Technical image quality will beat anything in 35mm, meaning far better than anything from Nikon, Canon or maybe even Leica.


More Information: Pop Photo mentioned the Pentax 645 in the June 1984 issue. It was announced at PMA in 1984.



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Thanks for reading!


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