We just spent a week shooting the new Pentax 645z, the new, somewhat-affordable medium format system. We wanted to take a real world approach to how we would test the camera, so like most reviews on Fstoppers, this will be less technical and more about how it performed on the job. It was put through its paces at full wedding, a weeks worth of portrait sessions and a night shoot.

Why Medium Format?

Medium format digital cameras have been on our mind lately, as the market is at an interesting point. There are rumours that most major camera manufacturers could be entering the medium format market as early as next year. There is also an abundance of used equipment available and the older CCD backs are great if you are able to shoot everything at base ISO. This is one of the many new medium format offerings to use the 51mp CMOS sensor produced by Sony. This new CMOS sensor is a huge deal for the way we shoot, mainly because it allows useable high-ISO and live view.

Medium format offers a few great advantages over 35mm: larger pixels, larger files, better color, and leaf shutter lenses. This all came at a cost, as until now a MF kit would set you back between $20k and $40k. It would shoot slow, it might have one AF point, and you would be stuck below ISO 400.

100% view.

Shoots Like an Oversized DSLR

We chose to specifically not use a tripod and we weren't shooting tethered. We wanted to see if we would be able to shoot it exactly like we'd shoot our Canon 5d Mark IIIs. We found the autofocus to be reasonbly fast in ideal to good light situations and very accurate. The battery lasted much longer than we anticipated- it showed 75% still remaining after being used for a full wedding day. This was also the first time we were able to use workable live view on medium format. The grip feels nice and sturdy in your hand, however the button placement doesn't seem to be as refined as Canon/Nikon. I’d love to see a joystick on the back for moving AF points and the zoom box in Live View.

Dynamic Range

There is a massive amount of detail in the shadows and the highlight retention is decent. I do recommend using live view for real-time blown highlight warnings, it is actually useful because it doesn’t use the preview jpeg to generate the warning, but the actual raw sensor data. Here is a shot that we underexposed by over five stops to test this. The colors stayed true and there were very little noise issues.

Before Lightroom adjustment.

After ( plus 5 stops in Lr and plus 100 Shadows)

Here is a better real world example showing why this can be helpful for our everyday. Shooting a couple in front of a sunset can be tricky- you want to capture the color of the fading sun and have more than a silhouette of your subject. This is easily attainable by utililzing the sensors dynamic shadow detail.

Exposed for sunset.

And after a gradient and adjustment brush in Lightroom.

Here is an example of a photo as it was exposed in camera, with basic lighroom edit.

High ISO

We set out after dark to take a few portraits of the lovely Jade Rose. We used an iPhone flashlight to light the first two shots and street lamps for the third. Up to ISO 12,800 is no problem, the colors stay accurate and you can still push the files in post. ISO 25,600 is doable under the correct conditions, or makes a great black and white.

ISO 12,800 | f/2.8 | 1/125th

ISO 25,600 | f/2.4 | 1/125th

ISO 6400 | f/2.8 | 1/125

Lenses

For lenses, we primarily used the Pentax 55mm f/2.8. The 55mm is equivalent field of view to about 43mm, and it performed well offering very little distortion and great sharpness wide open.

An interesting note about this camera, you can adapt the readily available and affordable Pentax 67 lenses. There are even a few 67 system lenses with leaf shutters, should you need them. We also used the 105mm f/2.4 from the Pentax 67 film camera with an adapter, and presently this is the fastest lens available for the system.

Auto Focus

The 27 point system is clustered near the center of the viewfinder, making it somewhat limiting. We did most of our shooting using the center point and recomposing. It was relatively accurate with most of the images we took being tack sharp at 100%. That said, it was fairly slow, difficult to nail focus on anything moving, and autofocusing in a backlit situations felt nearly impossible. The AF is also very slow and difficult when using Live View, but you can turn on focus peaking and manually focus very accurately.

The Files

The files are big and beautiful with brilliant color detail. They are the reason you would get this camera. Viewing the files at 100% revealed sharp detail. The files are large (8256 pixels x 6192 pixels), around 60mb each, so editing them takes a powerful machine or patience as a file renders a change. They edit very much like the Canon files we are used to in Lightroom and it was surprising how easy it was to match our editing across the two.

It hard to see how impressive these giant files are in this post alone, so we wanted to make a few avaiable for you to download and play with. Here are a few example files:

Full Resolution jpeg

DNG Files: High ISO & Couple Portrait.

We retain full copyright of these images, please don't steal them.

A few more example images:

A portrait of Portland Drum & Bass artist Revival.

ISO 100 | f/2.8 | 5 seconds

What we liked

The incredible files- 51 megapixels with great color, shadow detail, and dynamic range

Live view - We use this quite often on our DSLRs, the articulating screen makes overhead or ground level composition a breeze

The price- A digital medium format kit for under $10,000

What could use improvement

New leaf shutter lenses would be great for studio / strobe use.

AF speed could be improved, even though we think it is the best in the medium format game currently



The Pentax 645z is incredible for high-detail, beautiful portraits. I can’t wait to shoot a few landscapes, especially at night. It isn’t for everything and it won’t replace your 35mm... and honestly it shouldn’t. I think we’ll end up adding one to our gear bag and use it along side our other cameras. It will definitely get the call for commercial work, stock photography, and landscapes. Portraits are incredibly detailed and I can’t wait to see some of these files printed huge. This is definitely a game-changing camera and it should prompt a new gear battle in the digital medium format arena.