Advice: move to autofocus or not

[h._shafi]

Hi,

 

I'm pretty new to medium-format photography. Most photographs I take

these days are of my children (35mm film, MF film, and some digital).

I find that I'm missing out on a lot of great photos while I'm

focusing my manual focus Mamiya 645E. Is it worthwhile to switch to

an AF system (e.g., Pentax 645Nii or Mamiya 645 afd)? One of the

biggest lessons that I've learned so far with 645 is the shallower

depth-of-field. Will relying on an all-auto system make this problem

worse? Will I still be able to easily focus on "eyes" for example and

is the AF mechanism in the above 2 systems as fast as 35mm equivalents?

 

Thanks in advance.

 

-Haz

[iwong]

Moving children are probably one of the most difficult subjects you can photograph. AF medium format lenses don't quite match the speed of the best 35mm AF lenses, due to their greater size. Also the shallower DOF in medium format works against you. I found that manual focus using the hyperfocal method works best, forget about focusing on the eyes, you can never track them accurately anyway. Even if the best 35mm AF lens is fast enough to focus on them, by the time the shutter fires, the face has already turned away.

 

Just use a small digicam (advantage of small sensor and bigger DOF) that has manual focus capability, and shoot hyperfocal distance.

[peter_white2]

That's the problem. The camera doesn't know what an eye is, or a nose, or much of anything else. To be sure of getting that part of the image that you want in focus, you need manual focus. Unless Mamiya is doing something similar to what Canon does, which allows the camera to see what part of the frame your eye is looking at and focuses there, it's hit or miss, usually miss.

[edwin_chung]

Unfortunately in term of auto focusing, there are no medium format systems that can compare to 35mm systems. You will be disappointed if you are expecting 35mm auto focusing performance. That said, in general, auto focus, in most cases, are faster than manual focus. If you are heavily invested into a manual system, to me anyway, it does not make sense to switch. Auto focus might give you a couple more good shots (I mean in focus) per roll but it is expensive to switch system. If you are convince about switching to auto focus system, either system will be fine. If you pick Mamiya, you could use your existing lenses.

In term if depth of field, it is the same as your 645E (assuming you will pick a 645 auto focus system).

[david_holland1]

At least with a Pentax 645N, you will not be able to expect it to focus on the eyes, nor when depth of field is shallow will you be able to predict exactly where the plane is.

 

In my experience it doesn't even work with posed adults in a studio environment.

 

As others indicate, it's hard enough just to catch them looking at you, so modified hyperfocal is the best bet for small active children.

 

However, with a faster film, a smaller aperture, and some distance to the subject--for example full length rather than head and shoulders--you can get shots in servo mode even with fast moving subjects that you simply could not get any other way--for example an older child engaged in an athletic activity.

 

I have gotten excellent results with the 200mm lens and a child on roller blades at full speed, panning with her with the image almost filling the frame.

[raymond_petty1]

Haz, I have a Pentaz 645N that I picked up when the bottom was falling out of medium format gear as the digital revolution picked up speed.

This handles suprinsingly like a large 35mm camera (especially with the 75/2.8). No, it does not handle like my Nikon F-100, but then I never expected it to. It does handle far better than I expected and works great for my children of 8,5 and 4.

I made the leap for exactly the reasons you are stating, and was happy I did. Of course, YMMV.

[pavelp]

<i>To be sure of getting that part of the image that you want in focus, you need manual focus.</i><br><br>

 

Can't you just lock focus and recompose?

[peter_white2]

I suppose you can. But that means you have to carefully place the auto-focus sensor on the eye, being sure that the sensor is picking up just the eye and not the nose next to the eye, or the hair off the the side, and then hold that focus while recomposing. Sounds to me like it would be a lot faster to simply focus on the eye.

 

If the purpose of auto-focus is to help photographers with poor vision to get good focus, I'm all for it. But if the purpose is to speed up the process for the rest of us, I fail to see how it can accomplish that, except for extremely fast moving action like football or basketball.

[frank_kimble]

Use 800 film and a slightly wide angle lens and the smallest f stop you can use, This will get you a lot more DOF.

[pensacolaphoto]

If your eyesight is getting weaker and you have more than usual out of focus photos, I would consider an AF 35mm camera first. If you like the results, borrow an AF medium format camera from your local camera store and see if you like it too. There will be more money involved, obviously.

[Ian Taylor]

I photograph a lot of kids (and adults) with a 645N. I don't have any problem focusing on the eyes, and I shoot at f2.8 all the time. You just have to practice with the thing.