Do You Use Manual Focus UW?

[Peter Guy]

On another thread a professional photographer was discussing the pros/cons of certain cameras and opined that those cameras without useable manual focus were not of the same class as those with manual focus. (That is a paraphrase and NOT exactly what he wrote -- but we were discussing various classes of cameras and he wrote that to be in the top class, manual focus was necessary.)

That discussion got me to wonder how many people use manual focus underwater (or on land for that matter!). With my S80 I sometimes used MF but I could only really use it when: a. Macro; b. Stationary object (nudi); c. Stationary me! It wasn't a realistic alternative for 99.9% of my image taking. Now that I think about it, MF isn't a realistic alternative for 99.9% of my land based image taking (shooting pics of horses for example lends itself to autofocus).

Anyway, how many of you CAN use manual focus on your UW setups and if you can, how many of you DO use autofocus?

If you use MF, do you use the optical viewfinder? And if so, do you have an external add-on?

 

[Nemrod]

I use manual focus often. With ultra wide angle and fisheye lenses the depth of field extends from the dome port (or close) to infinity, thus once focused, I can leave the camera alone. This speeds up the shutter response considerably.

I also use manual focus for macro and close ups.

I hate autofocus and would wish for a digital camera with true manual focus and no autofocus. I can focus my remaining film Nikon SLR, FMII, just as fast or faster and it is focused on what I want in focus, not what a computer think I want in focus.

N

 

[davelew]

I use a lot of older manual focus only lenses underwater. There are two situations where I think autofocus gets in the way: wideangle photos and macro photos.

Wideangle lenses have such a large depth of field that autofocus doesn't really help, it just slows down the picture taking process. I generally use an autofocus lens for wideangle shots (the Zuiko 8mm f/3.5 fisheye), and I leave the camera body in manual focus mode for most of the dive. I occasionally turn on AF to switch the lens from CFWA to WA, then move it back to MF to stay there. On my rig that happens to be easier than turning the dial for MF, but that's just due to my peculiar camera rig.

For macro photos, I've found that autofocus doesn't work unless I and my subject are both very still. I can't get a good crisp macro image in terrible surge even with autofocus and the fastest focusing lenses I own. Even when I stay still, the autofocus sometimes decides that the rock is more important than the fish peeking out from behind it, and it's hard to get the tack-sharp focus on the eyes that make the best photographs (IMHO). I find it's a lot easier to get photos with what I want in focus using manual focus, and often moving the camera a tiny bit. There are times when I'm trying to take photos with a 160mm equivalent macro lens that I wish for perfect autofocus, but I know that when I can't lock the focus and move the camera to get the focal plane where I want it and press the shutter release, the AF computer won't be able to do that either.

There are some mid-range photos, neither macro nor wideangle, where autofocus is sometimes useful, but even for mid-size fish portraits I find that AF hurts as many of my photos as it helps.

This is just my own personal opinion. I know there are many photographers (Eric Cheng, for example) who are far more skilled than I am, and who use AF extensively. I just personally don't like autofocus.

 

[PatW]

Auto focus does pretty well in most uses. It even works pretty well for objects with a lot of surface texture in macro. But if you are taking a photo of a fish (smooth) with a rough background nearby (like gravel or coral). The auto focus will often lock into the background. So manual is better in those situations.

 

[tbone1004]

A lot of this depends on your skill as a diver... You can't do Macro period if you can't hover perfectly still...Wide Angle I just get a wicked fast lens, stop the sucker way down, and it's usually good enough to get just past the port. I shoot in MF almost all the time, just works better for underwater. Too much crap can fly past the lens and confuse the camera... That and a lot of the time what I'm focusing on isn't in the dead center of the frame so it screws it up even more.

That being said, the high speed focus on my Pentax works quite well and if I'm shooting moving fish or divers it tends to lock on to that faster than I can and it will hold it once it finds it.

 

[Peter Guy]

Thanks for the responses -- but, I'm curious as to the second part of the question to which none of you have responded. How do you determine you ARE in focus? Through what are you looking?

 

[Nemrod]

Thanks for the responses -- but, I'm curious as to the second part of the question to which none of you have responded. How do you determine you ARE in focus? Through what are you looking?

With an SLR you look through the pentaprism and there is usually a split image focuser or matte field focuser.

With my S90 I look at the magnified image supplied at half press. Once the focus is set for my purpose I leave it. If I were into macro, I would use a wand like I used to have for my Nikonos III, preset focus to the length of the wand and use the wand to set subject/camera distance.

N

 

[AndyT]

I use MF when shooting macro with the 50mm and 2x TC. I let the camera AF untill I have what I need in the frame and then hit the MF button. Then it is a matter of rocking the camera back and forth untill the image looks to be in focus through the viewfinder. Usually takes a few attempts to get the framing and focus right - patience is a virtue !

I should also use this method for my WA shark photography as well, but I usually forget to switch to MF ................

 

[Peter Guy]

OK -- I'm getting the sense here that most of you are using, in essence, fixed focus for the shots rather than focusing each shot. Am I right?

BTW, when I tried to use the optical viewfinder on a friend's dSLR, I had so much trouble seeing anything worth while that I can't imagine using it for focusing -- combination of "old eyes" and mask. I understand there are add-ons which make looking through the lens while wearing a mask much easier.

 

[davelew]

OK -- I'm getting the sense here that most of you are using, in essence, fixed focus for the shots rather than focusing each shot. Am I right?

For WA, I use fixed focus and don't touch the focus knob.

For Macro, I fix the focus for that particular photo, and then move the camera. Between subjects, I will turn the focus knob, but for each individual subject I use fixed focus.

I also look at the preview screen and zoom in to make sure I'min focus. Live-view doesn't slow down my camera in manual focus mode, which is another reason to go for MF.