M8 Focusing vs. todays DSLR

[roblumba]

I heard that Leica rangefinder technology is superior in focusing because of the rangefinder base. I bought the Leica M Advanced Photo School book and read the section on how a larger base reduces the effect of human eye error on the focus error.

DSLRs are very limited because their base is constrained by the aperature of the lens. However, today's DSLR, such as my 1DMarkII do not use the human eye to focus. So how does the electronic focus error on a pro level camera such as the 1DMarkII compare to the focus error of the human eye on a Leica rangefinder?

 

[jaapv]

That is basically an unanswerable question, as it depends on the "quality" of your eye. Canon defines their focussing error on their pro series as "within 1/2 DOF" afaik.In practice I feel that on a M camera, with a 50 mm lens I can double that accuracy.

 

[MCTuomey]

Anecdotally, since I shoot both Canon 1D and M-bodies, I think the rangefinder has the edge. But it is a rather forced comparison, at best. I usually shoot normal lenses on my Leica body. I shoot tele lenses with my 1D (youth sports), primarily.

Rob, what prompted your question? Is there a particular use you're considering for a rangefinder?

 

[roblumba]

Rangefinder Focus Application

Rangefinder Focus Application

I was planning to use it for people in their surroundings and portraits. Basically I was considering the 28mm 2.8 Elmarit or a 35mm as my starting lens and going for a 50mm or 75mm sometime down the road for a portrait lens.

 

[ghost]

they both do their jobs well, and there's no cause for concern. if you're going to photograph people in their surroundings, go with the 28mm.

 

[newyorkone]

I was planning to use it for people in their surroundings and portraits. Basically I was considering the 28mm 2.8 Elmarit or a 35mm as my starting lens and going for a 50mm or 75mm sometime down the road for a portrait lens.

At these focal lengths, the differences will probably be very slight.

 

[MCTuomey]

I was planning to use it for people in their surroundings and portraits. Basically I was considering the 28mm 2.8 Elmarit or a 35mm as my starting lens and going for a 50mm or 75mm sometime down the road for a portrait lens.

Rob, I think once you learn the technique associated with RF focussing, you'll have no problem with wider lenses due to DOF latitude even at max aperture. (If that's already obvious to you, my apologies.) Fast 75 and 90mm RF lenses become more difficult to focus consistently due to the tighter DOF, but many users do fine with them as well. Part is technique, part is native visual acuity, part is magnification of the viewfinder.

By the way, I believe the center focus point on Canon's 1D bodies are designed to be accurate to the middle third of a given lens' DOF, relative to Jaap's comment above.

 

[georgl]

The M8 with 0.68 viewfinder-magnification is about as precise as a SLR with 90mm lens, more precise <90mm, less precise >90mm.
Especially with the extremly sharp and fast WA-lenses on the M-system you will notice rather quickly (especially when using it digital with 100% crops) that DOF is an illusion ;-) I prefer focussing with the M-system - it's very precise but not nearly as fast as the best AF-systems out there.
You want to make sports-photography? Nikon D2 or Eos1 is the best solution.
You want to set the focus to an exact point in your picture while using high-speed-lenses <135mm? With good eyes the rangefinder-system is superior.

 

[JohnL]

That is basically an unanswerable question, as it depends on the "quality" of your eye. Canon defines their focussing error on their pro series as "within 1/2 DOF" afaik.In practice I feel that on a M camera, with a 50 mm lens I can double that accuracy.

I read somewhere that it's within 1 DOF for lenses slower than f/2.8 and within 1/3 DOF for lenses of f/2.8 or faster. I'll try to find where I saw that.
I also read something somewhere to the effect that SLR focusing accuracy is related to focal length, so that with long lenses SLRs focus more accurately. For normal and wideangle lenses, RFs are inherently more accurate.

 

[MP Guy]

keep in mind that most AF cameras have selectable focus sensors. I never understood the way it workd. All I know is that I got good pictures most of the time but some were focused on the wrong spot

 

[roblumba]

I'm more towards wide.

I'm more towards wide.

My shooting style tends towards the wide and normal focal lengths, and rarely do I try to do sports. The only reason I would do sports is for fun, but I don't need it and rarely use my DSLR for that purpose.

 

[roblumba]

Selectable Focus Sensors

Selectable Focus Sensors

Jorge, I'm really a focus selection nut on my 1D MarkII with 45 autofocus spots to choose. That' the one thing I fiddle with the most often. I'm always moving that little red box around so that I can focus and do minimal recomposing. I find that most of my shots, even wide open, are very well focused.

 

[Allen Gilman]

"So how does the electronic focus error on a pro level camera such as the 1DMarkII compare to the focus error of the human eye on a Leica rangefinder?"

depends on....a lot of factors. in practical terms, i wonder how much you really should be worried about this given the shooting conditions you've described. i'm guessing that what you're really worried about underneath this is a situation where you'd have to focus and recompose? if so, then it's a matter of faith (in your judgement of distance) and practice if you're shooting with a rangefinder. otherwise, either one would do just fine to get excellent results. i wouldn't worry about it too much tho - things disappear when you fiddle around too much (i.e. women).