Further Adventures in Medium Format - Fujifilm GFX 100S

As faithful readers of these articles know, I moved from shooting in (digital) 35mm format to (digital) medium format in 2012. I started with a 40 megapixel Pentax 645D and moved in 2015 to a 52 megapixel Pentax 645.

I enjoyed shooting with both those DSLRs and they were my go-to cameras for the last nine years. The increased quality of the images from those cameras convinced me not to ever go back to the smaller 35mm format. But, much as I appreciated their overall performance (of the 645Z in particular), I became less and less excited about taking them out into the field due to their weight and bulk.

Here’s what I mean: the 645Z by itself weighs 3.42 pounds. But you need a lens. A short telephoto lens, such as the HD Pentax-DA645 28-45mm F4.5ED AW SR, weighs in 3.24 pounds. The camera + lens package comes to 6.66, and that just seems to get heavier and heavier each mile on the trail!

So when higher-end mirrorless cameras began to emerge, I was ready for a change. Remember that the “R” in SLR/DSLR stands for “reflex”: the mirror that permits the photographer to view through the lens and see exactly what will be captured, and then flips out of the light path when the shutter is pressed so light can reach the film/image receptor and the image. A mirrorless camera, by definition, lacks that mirror and its accompanying complexity.

A quick illustration is below: the left camera body - an SLR - needs to have room for the mirror (in blue) to swing out of the way when the shutter is pressed so that light can fall on the film or imaging sensor. The right camera body - mirrorless - can be significantly shallower because there is no swinging mirror to accommodate. There is also an overall reduction in the complex parts of a traditional SLR, which can further shrink the necessary volume of the camera. (illustration by Shigeru23, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons.)

dslr v mirrorless.jpg

You can see the potential reduction in size and mass from eliminating the reflex mirror. This is particularly effective with a medium-format DSLR because of the larger sized mirror necessitated by the larger sensor. The potential to remove volume and mass from a camera body by eliminating the need for the mirror box is the key to creating a smaller and lighter camera system.

Getting lighter!

Moving to the specifics I worked with, I wanted a smaller and lighter camera with - if possible - increased resolution. I was drawn to Fujifilm’s 2019 release of their GFX 100, but while the 100 megs was very attractive (I like to print large, particularly large panoramas), the size and weight of the body was just not the improvement I needed.

When Fujifilm released the GFX 100S early year, I knew I had found the sweet spot for my needs: smaller and lighter with double the resolution!

This is comparison I made:

  •   Pentax 645Z: 6.14 x 4.61 x 4.84 in. (total volume 137 cubic inches); 3.42 pounds

  •   Fujifilm GFX 100S: 5.91 x 4.09 x 3.43 in. (total volume 82.9 cubic inches); 1.98 pounds

Those numbers are revealing, but I think it is more helpful to see the two bodies side by side. Here is a composite image of the two cameras (taken several years apart) scaled to match on a one-inch ruled sheet in my studio, lined up on their backplates:

bodies compared.jpg

As you can see, the overall volume of the 100S is about 60% of that of the 645Z, with the major reduction being the front-to-back distance. That major change is the direct result of the removal of the mirror which was needed in the 645Z.

The other issue is weight: 3.42 versus 1.98 pounds. The 100S comes in at 58% of the weight of the 645Z, and that 1-½ pound reduction is definitely a difference you feel carrying the camera in your hand.

Now combine each body with an appropriate short telephoto lens, such as the HD Pentax-DA645 28-45mm F4.5ED AW SR and the  Fujifilm GF 35-70mm F4.5-5.6 WR. The Pentax lens weighs in 3.24 pounds while the Fujifilm hits the scales at just .86 pounds. The camera plus lens packages are thus 6.66 pounds for the Pentax and 2.84 pounds for the Fujifilm - a difference that is now over 3-¾ pounds!.

I have settled on three lenses for the 100S at this point:

  • the GF 35-70mm F4.5-5.6 WR as my short (landscape) zoom;

  • the GF 50mm f/3.5 R LM WR as my walk-around lens; and,

  • the GF 100-200mm f/5.6 R LM OIS WR as my long zoom.

The 50mm is almost a “pancake” lens, measuring less than 2 inches long and weighing ¾ of a pound. The 100-200mm is necessarily larger, coming in at 7.2 inches and 2.3 pounds. But together the three lenses put just under four pounds into my backpack, compared to about 7-1/2 pounds when I had a matching collection of Pentax lenses. Total: 11 pounds for the Pentax kit versus 6 pounds for the Fujifilm collection!

That five pound difference is equivalent to over two liters of water, and is a very meaningful improvement in my (not very humble) opinion. I have quickly come to appreciate the reduced load from that kit, whether I am toting everything in a backpack to get to a shooting location or holding the camera and lens at the location as I search for the perfect shot.

Image Quality

None of this would matter if the image quality of the Fujifilm gear did not meet my needs. You know from this site that I am a professional landscape photographer. I’m based these days in New Mexico, and I’m one of the owners of the Albuquerque Photographers’ Gallery in Old Town Albuquerque (www.abqphotographersgallery.com.) Buyers of my prints expect very high quality, and I like to create and sell large panoramas as well as more traditional dimensions of prints on infused aluminum, canvas, and fine-art papers. Being able to offer high-quality finished prints requires excellent image capture and quality in the camera.

I am pleased to join other photographers in praising the quality of the 100S. The value of expansion of resolution from 50megs to 100megs is immediately obvious.

A day after getting my 100S, I went to the top of the Sandia Mountains on the east side of Albuquerque and took some quick shots down into the metro area.

Sandia-ABQ F0023.jpg

This shot looks down more than 4500 feet down to the valley floor, and on the right edge of the image the neighborhood is over 10 miles away. Yet even on this hazy day, I can zoom in on the image from the camera and make out individual homes in that neighborhood! So, yes, there is plenty of detail!

Here’s another example, this time from the Toadstools hoodoos formation in southern Utah, on the way to Zion National Park. First is the image from the camera, with only some color correction, and no sharpening.

Second is an enlargement of the  boxed area in the first image, showing the detail in the top of that toadstool. The full image is 11,648 X 8,736 pixels, or 39 X 29 inches at 300 dpi right out of the camera. So even this small crop has a more-than-adequate amount of detail in the crenelated rock.

Three Toadstools example F0144.jpg

Three Toadstools closeup F0144.jpg

In addition to the bounteous resolution, I have also been impressed with the in-camera image stabilization. I took the 100S to Zion National Park just before Christmas. Thanks to the image stabilization, I was able to hand-hold shots that I would normally have expected to need a tripod. This image from a rather rather gloomy day was shot handheld at 1/18 sec.

And here’s a crop showing just the lower-right corner of that shot, to demonstrate the lack of any camera-motion blurring, even in these low-light conditions with a longer exposure than I would have attempted with any of my previous cameras.

Virgin River F0231.jpg

Closeup F0231.jpg

While I do use a tripod in the field, having the flexibility to get shots hand-held is a significant practical advantage of the 100S.

Image Files

I shoot in raw for use in any serious editing, so I dedicate one SD card slot for those saves. I use the other slot for JPEGs that are smaller and can more easily be shared or emailed when I am out of the studio. Raw files can be quite a bit larger than JPEGs; the raw files from my Pentax 625Z with its 50 meg sensor saved at between 60 and 75 megs each. As a result, I was concerned about managing captured files from the 100 meg sensor in the 100S.

Fujifilm provides three choices in how you save raw images to the two SD cards. These are:

  • “Uncompressed Raw”

  • “Lossless Compressed Raw” where Fujifilm says the images “are compressed using a reversible algorithm that reduces file size with no loss of image data”; and,

  • “Compressed Raw” where image are compressed using a “lossy”, non-reversible algorithm and Fujifilm says the quality is “about the same as Uncompressed.”

In each instance, the file can be saved in 14-bit or 16-bit mode.

I’ve never worked with a compressed raw option before, and decided look more closely at the save formats to see what sort of differences in results I could see. I did a comparison of the same shot saved as all six ways: Uncompressed Raw 14 + 16, Lossless Compressed 14+16, and Compressed 14+16. I reached two conclusions: for my work, there was no meaningful difference between the 14-bit and 16-bit versions; and, Fujifilm’s descriptions were accurate, in that I did not see any difference between the Uncompressed Raw and Lossless Compressed files, but did see a small degradation when I compared the Compressed files.

Based upon those results, I have been shooting in Lossless Compressed. There is a penalty in that choice from the resulting file sizes. Lossless Compressed files come in at about 120-125 megs, while Compressed files fill 60-65 megs on an SD card. Those are both considerable savings over the 205-210 megs for Uncompressed files.  They all open to about 290 megs in Photoshop, so the Lossless Compressed format is quite effective in trading off space versus quality.

What's next?

That's it for my early reactions to the 100S - as you can tell, I am very pleased with it for my landscape work! I'll be adding additional thoughts to this report, so check back!