In my opinion the ZD Back is not the best choice for people photography but this depends strongly on how your style of shooting is. If you are used to capture "the whole moment and decide later what to keep" than you won't like ZD Back.
Buffer: One of its limitations is not that often quoted tiny buffer of 11 frames. It's the fact that it takes up to 10 seconds to save an image which is really annoying and I don't think they changed the writing speed on the "double buffer" model. So if you fill up that buffer it takes over a minute to clear it. While it is clearing the buffer you can't continue shooting, you don't even have access to the menu... However, I rarely shoot 11 continuous frames.
ISO speeds: Well, there's not that much to say is there? Sure it's nice to have at least the option to push it up to 400 but should you do it? My answer: Not as a professional who aims to deliver excellent image quality.
Reliability: Now that's the striking point. Let's just say the ZD Back has its own character... :ROTFL:
No honestly, it really is unreliable as hell. I have to reset mine at least once per shoot. Sometimes it refuses to write an image to the card (the decisive image
). Lately, mine decided to prefer SD cards over CF cards. If a CF card is mounted it won't start up.
Exposure times: Anything longer than 4 seconds results in colour noise. It's not too much of an issue as you are post processing your files anyway. Don't get me wrong, even exposures of 30 seconds can look great if take your time to work on that noise...
Purple worms: These "purple worms" or "blobs" may occur if there is too much reflection or a light source pointed towards you. I wouldn't worry too much about them. You'll never see them if you strictly expose for shadows.
Having said all this, is there anything good about it?
There surely is:
IQ: It delivers excellent image quality as long as you keep it on its terrain. At ISO speeds of 50 to 100 images look outstanding.
Post processing: I like working on the ZD files more than I ever liked to work on the output of my 35mm gear. Maybe it's totally subjective feeling but I believe I can adjust things quicker and with better results.
Cost performance ratio: Well, I think it's quite alright...
White balance: In addition of the "common WB settings" it let's you choose from two manual WB settings and you can even choose to adjust the temperature between 2000 K and 10000 K by yourself.
Feel: It's pretty light. Mounted on a Phase/Mamiya body you can shoot handhelt without too much trouble.
Conclusion: IMHO The ZD Back is a great way to get familiar with digital medium format. However I wouldn't want to shoot an entire weddings with it. At least not the documentary part (What's the correct word for it? In german it's called "Reportage"). If you want to use it for portraits of the bride and groom and you can control the lightening it might be a great benefit.
Wow, this response got longer than expected. Sorry guys, it's late and I'm tired so I guess I exaggerated a lot here... :sleep006: