M43 vs P&S vs DSLR upgrade for low-light informal shots?

I don't see the problem with shallow depth of field really. Set up your 5d with center focus and tell them to point at people faces and recompose. It should work unless you have like a 85mm 1.2 on it. Use a 28 or 35mm...

FWIW use a rough estimate of 1.5 stop incremental for premium p&s, m4/3rd, aps-c and FF dslr.

Why not buy a cellphone like your freinds instead of taking your DSLR where it doesn't belong.
We frequently say it is the person behind the camera which is important not the tool.
Is it really important that such photos have to be crisp sharp like our commercial or art work?

Devon:

If it's too dark for the 5D, it's going to be too dark for the current compact cameras in terms of noise at higher ISOs.

Best option for non-camera users in a low lit coffee shop is a mug of coffee. Low light is challenging. There isn't a point and shoot that anybody can operate that will give good quality photos in light dim enough to cause problems for the 5D.

JC, if it's too dark for the 5D, it's too dark for cell phone cameras.

Eric

I love shallow depth of field people shots, but, having tried to simply explain the techniques involved multiple times (in a foreign language), I've come to the conclusion that I need a new approach (@Leslie). I also have a cell phone, but my friends have that angle covered masterfully! The person not the tool is exactly my point: my friends are enthusiastic and most want to give a DSLR a go, but they aren't knowledgeable about photography, and they tend to get lots of sharply focussed shirt fronts/booth panels etc. with blurry faces. I'm just trying to find the most approachable tool for absolute novices. In my experience, my friends are pretty happy when I present them with a shot of them that is nicely photoshopped and has a more polished look to it (@JC Uknz). It's become a way of sharing my hobby with my non-photographer friends and has generally been well received as long as taking pictures doesn't dominate the entire time spent together.

@Eric: Yeah, I kind of thought that would be the answer. Perhaps future upgrade to the 5DII (or III whenever it comes out) and use of Live View to explain the concepts even better will be the best option.

Thanks for your thoughts.

Have been trying to attach an example, but it isnt' working. FWIW, JEH 01 in my people gallery. http://photo.net/photodb/photo?photo_id=15078813

Most of the pictures I looked that had EXIF data were taken with a 85mm lens and typically your aperture is around 7 to 8.

There are only two things you can do to get more light and more depth of field. Use a shorter focal length lens and use a wider aperture. Short focal length lenses for any given aperture will have more depth of field than a longer focal length lens. Shooting at a wider apeture will give you more light but reduce the depth of field. You will need to experiment with different focal length lenses and apertures to find a combination you will like.
You can also crop in post to compensate for the greater field of view of a shorter focal length lens.

You need flash so just shoot a pic now and them if people start getting irate.

Try M4/3. I'm serious.

First, you can run a fast lens, such as the Oly 45mm f.18 (FOV is about a 90mm on your 5d), or other native, fast lenses. Then, the CDAF systems allow for face detect. So your friends point, let the camera find the face, and shoot. Just set the apreture open enough to let in a decent amount of light and go. Plus, they are much smaller, so, less stuff to lug around.

Just to be clear... only picture JEH 01 (in that gallery) is shot under the conditions that I mentioned earlier. The others in the gallery are largly daylight portraits taken outside where focal length and aperature weren't really issues.

@Zach Yeah, I was wondering if face recognition and the smaller size would help my friends. Some of them struggle with a 5D and L lens combo. Thanks for the tip.