I've been doing a lot of reading lately and am just about ready to jump on the DSLR bandwagon, but I'm having a hard time deciding what to go with. The GH1 is looking really attractive right now, but what are some of the drawbacks I should be aware of when compared to saving up longer to get a 7D? Basically, how do the 7D and the GH1 compare? is the image difference substantial? hows the jello effect on each? etc. etc.
DOF possibilities is a major thing to consider. The micro 4/3rds sensor on the GH1 is smaller then the APS-C sensor on the 7D so you'll have to work harder (longer lenses, moving further way) to achieve the same shallow depth of field. Some also say its noiser - to me it seems about the same.
Also finding lenses for the micro 4/3rds sensor is more difficult. With the 7D you have a ton of OEM lenses to choose from as well as the ability to adapt Nikon lenses as well as use lenses from Ziess, Tamron, Tokina Cook and others and if you really want to dish out some cash adapt PL mount lenses like those from Panavision (although you can't buy the Panavision lenses)
I beg to differ from Robbie. Your comments on DOF and lens choices are inaccurate.
In terms of DOF, the difference between 7D and the Gh1 is rather small. In practical settings out in the field, I don't think it makes much difference.
The larger the sensor / film area, the more shallow DOF. Here are some figures to look at:
Motion Picture 35mm, 1.85:1
20.96mm x 11.33mm (diagonal: 23.83mm)
12.52mm x 7.41mm (1.69:1 / diagonal: 14.55mm)
APS-C (Canon 7D)
23.7mm x 15.6mm (1.52:1 / diagonal: 28.37mm)
The sensor size: 18×13.5 mm (22.5 mm diagonal)
imaging area: 17.3×13.0 mm (21.6 mm diagonal)
m4/3 is 10% smaller than 35mm motion picture, 30% smaller than Canon 7D. It is still much larger than super 16, and much much larger than any video cameras, even 2/3"varicam or F900.
Regarding lens choices, m4/3 is known for being one of the most adaptable camera ever. With its very short flange depth, you can find lens adapters that allows you to use pretty much use any lens made in the last 40 years. Just check ebay for micro 4/3 lens adapters. You will be amazed by the whole new world of possibilities with lens choices.
My own lens package for GH1 video shooting consists of lenses from Leica-R, Leica-M, Contax Zeiss, Nikon, Olympus OM, and even some c-mount bolex lenses. Hotrod Camera even makes a PL-mount lens mount for the GH1. No custom modification needed to use PL lenses.