Originally posted by Gerd Subject. high ISO performance:
I have the D810, the 645Z and the Fuji GFX.
The D810 is a power at ISO 64 in the studio. But with higher ISO performance it has nothing to counter the 645Z and the GFX. You can see the difference as from ISO 800. It remains to be seen where the D850 of the ISO performance will actually stand. You should also consider the PixelPitch. The D810 has a pixel pitch of 4.87 μm. The new D850 should have a PixelPitch of 4.35 μm (Sony A 7 RII of 4.5 μm). This will make it the D850 not really easy to make very good high ISO achievements. I would be glad if it would be on the level of the D810. For comparison the 645Z / GFX have a PixelPitch of 5.32 μm. If you want to have really good picture quality, the small pixels of the D850 also restrict the choice of lenses at Nikon.
Subject. Flash:
The 645z has fewer possibilities/performance with the flash than the Fuji GFX and the D810 (D850 presumably synonymous). The new lightning triggers have enabled the 645z a lot, but unfortunately there are many deficits. For example - the 645Z can not easily flash on the second curtain (this is annoying at moving images in many situations). The 645Z tries to calculate the flash power with a TTL device (which is necessary for HSS and SuperSync). For this purpose, it requires minimal aperture, shutter speed, and distance measurement. If one of these factors is missing, the 645Z will stop the flash. What the case is with manual lenses without aperture transmission. The GFX does not. It always triggers TTL even if the aperture value is missing. And it also triggers the flash "always" without TTL device. That goes with me to 1/160s without which a shading or a curtain in the picture is to be seen. The manufacturer/flash support is unfortunately with Nikon and Fuji significantly better. What I find very bad, but Pentax itself has since made no decisive step.
I can not draw a clear summary.
In the studio (almost) 100% decides the light I set. The differences between the formats/cameras are then only to be seen, if one knows exactly what one must pay attention. The situation is different in ambient light or mixed light. Since the 645Z and the GFX are in my opinion clearly advantage. The tonal values are however the small medium format cameras - with me - always better as well as the details. I use the GFX with all Pentax 67/645 lenses as well as many Mamiya RZ / RB / 645 lenses. The camera lens combinations deliver excellent results. But clearly with the reference in the GFX (with the Pentax / Mamiya lenses) at the time without AF.
Greeting Gerd
Thanks!
This is what I'm affraid with the 645Z, that I won't be able to do some things with flash and HSS, I was unaware that HSS only works with AF lenses, I have a Cactus V6ii for the 645D, but have never tried to use it with manual lenses, only the 3 FA I have and found no problem in my limited testing.
I do love the feel, the sound and even the weight of Medium Format, I shoot a lot of Medium Format film for personal stuff, but it's very expensive, per picture. I would love to stay in Medium Format digital, but I'm affraid I will be limited by some things, like I am now with the 645D. And going the GFX route is more expensive for me. I would need to spend just $6,500 for the body. Having to sell my 645D and lenses just to get a single lens or maybe two. The only reason I have a 645D is a found a bargain here in Mexico, a 645D body(3,000 actuations) and 3 FA lenses (45mm,75mm and 200mm) for $1,500 USD.
That's why I'm considering the 645Z, it will be the least expensive for me, since I only need the body and two relatively cheap lenses(120mm Macro, 150mm 2.8) around $700 USD each.
I have a lot to think, but have the time to do it, I still need to see if I can make it into the market and if it's worth paying that much in gear. For my personal work I would keep the 645D and add a FF 35mm, and keep shooting all of them.