I'm a commercial photographer based in Dayton, Ohio (but soon in Santa Rosa, California!!!!). I use a Sinar 4x5 with a Leaf Valeo. And it's pricey for my setup.
1. A Sinar F2 is around $700 used. The problem with Toyo View and Horseman 4x5 is that the Kapture Group sliding back adapter WILL NOT work with these 4x5 cameras.
2. A Leaf Valeo Digital Back is around $5000-$10,000 used; the Valeo 11, 17, or 22. And that's if it comes with the adapter ring (For Hasselblad, Bronica, Mamiya, etc.)
3. Then there is the Adapter Plate from Kapture Group.
That's another $2,000 dollars. Good luck finding one used that matches what you have in the large format area. I had to buy mine brand new.
So it comes to almost $10,000 dollars (roughly) just for the camera setup, not including carrying cases/hard cases, large tripod, equipment toolbox with level-tape measure to calculate what exposure (due to light fall off inside the 4x5) you're going to have, etc.
What are you going to capture to?? A desktop is fine if you're only going to shoot inside at a studio but what if you want to take a 4x5 shot at a location??
I have to do it all the time for clients at any architectural shoot.
That's where the laptop comes in. I think all digital backs are firewire (at least all the ones I've worked with) so no MacBook Air. The least to get would be a MacBook, but I suggest the MacBook Pro because it doesn't come with a glossy screen. A glossy screen will not give you accurate color correction. Also keep in mind that each shot from a digital back, in RAW format, is going to be anywhere from 70MB-150MB+ with 39Megapixel backs being far more! So each location is going to be a lot if you don't have a backup drive.
So really, it comes down to this:
Sinar F2 (used): $700 (from KEH.com)
Leaf Valeo (used): $7000
Kapture Group Digital Back Sliding Adapter: $2000
MacBook: $1700
Good Tripod: $300
Light Meter, 4x5 essentials: $200
Total Price (rough estimate, your total may be different but not by much):
$11,900 if almost everything is used.
Now this is based on my setup for what I do as a commercial photographer:
Sinar F2 (used): $700
Leaf Valeo 11: $5000
Kapture Group Adapter: $2000
MacBook Pro: $3400
Good Tripod (Induro Tripods): $350
4x5 essentials: $200
Profoto Lights: $3600
Mac Pro Octo w/ 2 monitors: $8000
Mac Pro Quad w/ 1 monitor: $4000
Misc: $2000
Total: $29,250 worth of equipment. This isn't including insurance, other items, expenses, etc. Just some of the major equipment. I'm even leaving some of the stuff out!
Now here's some examples of 4x5 stuff I've done with my digital backs:
