Let's talk "focus".

Dick on Aruba

I'm mainly into nature photography and the most of the time the preferred focus must be on the eyes of an animal or certain part of a flower etc.

Sometimes you (I) think it's in focus but if you look closer you discover you "missed". If you have the zoom-capebilities like my Nikon D200 than it's no problem, you just shoot again.

I wonder if this is a common thing to happen or not.

If a subject if far away, you can't "pin-point" on the eyes because the whole head is in the focus-square. I hear also about special focus-screens that make focussing easier / more succesfull.

What is you experience?

Dick.

John Desjarlais

Dick,

I definitely have that issue fairly frequently, and it's most often associated with using the autofocus. I've been told and have read that one should in general use autofocus because modern autofocus is more accurate than one's eyes (particularly true with my bad eyes), but this becomes a problem when the bug's/animal's eyes you're trying to focus on are larger than the sensor area (as is true with macro or superzoom situations). So sometimes I'll switch into manual mode for such situations, and I'm occassionally rewarded for it.

Another factor could be that for many cameras the central autofocus sensor is more accurate than the others, since it uses both horitontal and vertical autofocus criteria. So if you're often using the other sensors, perhaps that could be an influence as well?

Or maybe sometimes it's just bad luck ...

Dick on Aruba

Thanks John and Welcome to Dgrin!

There are a lot of factors that can make you mis-focus. If you shoot a lot of animals like me, the animal can move slightly by own will or wind and make you loose the focus especially if you use a very low f-number.
You can move slightly by wind or unstability. A tripot is not always handy in nature photography.

The D200 is a smart camera and I have more focus-keepers than my D70.

Maybe there are solutions / tips / tricks to improve all this and that's why I posted this thread. Dgrin have a great bunch of people that really love what they are doing and surely some of them have some usefull information.

Dick.

Harryb

Hey Dick,

There's really no simple answer here as there are way too many variables. You can go with AF-S (single-servo AF of AF-C (Continuous-servo AF). Then you have to opt for single-area AF, Dynamic-area AF, Group Dynamic AF or Dynamic area AF with closest subject priority. Then of course you always have manual focusing available.

There's no hard and fast one rule fits all here. When I focus I rarely try to focus on the subject's eyes unless I'm in real close to it. I usually go for the shoulder as its a lot easier to lock in on. I try to stay away from the center reticule for focusing because then you will end up composing the shot in your post work by cropping the shot. I prefer to use the left or right of center reticules and compose the shot when I take it This way I end up cropping less if at all when I process the shot.

Dick on Aruba

Harryb wrote:

...I prefer to use the left or right of center reticules and compose the shot when I take it This way I end up cropping less if at all when I process the shot.

Thanks Harry.

It make a lot of sense to do so.

I lock the focus and recompose which can give me in some cases an OOF also.
Next time I give your way a try.

Dick.

John Desjarlais

Another thought - wondering if you guys have tried using backbutton focus? I went to a seminar by John and Barbara Gerlach, and they recommended it. I promptly reprogrammed my D70 to set the focus on the AE/AF lock button. Then you set the focus mode to continuous servo. Then you continously focus using the backbutton, release it when you're locked in, and you can then easily recompose. I haven't gone back. Harry, I'm thinking Ron Reznick uses this technique as well?

Dick on Aruba

John Desjarlais wrote:

...I went to a seminar by John and Barbara Gerlach, and they recommended it. I promptly reprogrammed my D70 to set the focus on the AE/AF lock button. ...

Thanks John.

I did try this also with my D70 and did not like it very much. I keep on using the AE/AF lock to lock the exposure which I do very often.

Dick

Harryb

John Desjarlais wrote:

Another thought - wondering if you guys have tried using backbutton focus? I went to a seminar by John and Barbara Gerlach, and they recommended it. I promptly reprogrammed my D70 to set the focus on the AE/AF lock button. Then you set the focus mode to continuous servo. Then you continously focus using the backbutton, release it when you're locked in, and you can then easily recompose. I haven't gone back. Harry, I'm thinking Ron Reznick uses this technique as well?

Ron recommended that during the workshop I took with him in 2003 and I've been using it ever since. However this requires that you lock focus, hit the button and keep it depressed while you recompose the frame. It works but if you can compose the scene while locking focus with one of the right or left reticules you save a step and its faster.

There's no hard and fast rule here other than to do what works for you. In his DVDs Ron talks about looking at a scene and figuring out what you want to do before you start shooting. That works very well for me. My best shots have come when I have been prepared (knowing the exposure setting, knowing what elements I wanted in the shot and how I wanted to compose the scene). Here's one of my favorite recent shots.



I had been tracking the bittern for awhile. I knew the direction he was heading in and I knew he would be heading for this area of the lily pads. I wanted to focus on him as he came out of the lower right of the frame headed towards the upper left. I wanted to get the water lily close by him because its sort of pointing in the same direction he was going in. I also wanted the other water lily in the upper left of the frame OOF to simulate distance and a destination for the bittern. I knew before the shot that the center reticule would not do as the focusing reticule so I used the lower right reticule and focused on his left wing. I was in AF-C and Dynamic area AF with closest object priority.

My main point here is that what AF set-up is best depends on the shot you are trying to take. We have to understand how the different AF modes work and which is best for what we are trying to capture.

John Desjarlais

Excellent points, Harry, and a beautiful shot! I agree, I too change my use of the AF points depending on the situation. Lately, I've been getting more comfortable with my tripond and Kird BH-3 ballhead, which makes it easy to recompose after using the center AF point. However, with macro and very shallow DOF, I often wonder how a very slight recomposition affects the focal plane.

Harryb

John Desjarlais wrote:

Excellent points, Harry, and a beautiful shot! I agree, I too change my use of the AF points depending on the situation. Lately, I've been getting more comfortable with my tripond and Kird BH-3 ballhead, which makes it easy to recompose after using the center AF point. However, with macro and very shallow DOF, I often wonder how a very slight recomposition affects the focal plane.

I'm nit sure about macro shots. O usually use manual focus when I shoot macros.

Dick on Aruba

Dick on Aruba wrote:

...I hear also about special focus-screens that make focussing easier / more succesfull....

Somebody any experience?

Dick.

gtc

i have a katzeye plus focus screen on my 20d as i use manual focus pentax smc takumars.

its a fresnel/microprism ring with a split circle inside it-just like old film cameras.

its ok for slower moving animals especially if they are coming towards you-i usually prefocus to where they are heading and wait for them to become clear in the microprism ring and quickly stop down as far as I can within hand holding shutter speed limitations, and shoot-kind of cumbersome but do-able with some practice.

with stationary subjects it is very accurate.

i would not reccomend this as your primary method of focussing if you have AF , but its a good addition for finer focussing.

it is however very useful for macro and portraits etc.

i may add an AF chip to my m42 pentax to eos adapter to get focus confirmation for faster subjects-a beep and green light would be nice.

search dgrin for 'manual focus confirmation fix'
thread and 'katzeye first impressions'

Dick on Aruba

gtc wrote:

i have a katzeye plus focus screen on my 20d as i use manual focus pentax smc takumars...
...

with stationary subjects it is very accurate.

i would not reccomend this as your primary method of focussing if you have AF , but its a good addition for finer focussing.
...

Thanks for your input.

My general impression of reading about the Katzeye from people that just installed it was more than positive.

They installed it, run to the nearest cat, dog or flower and take a couple of shots. A big "WOW!" of the forum wand me to buy a Katzeye also.

Time will learn that all that "WOW!"-jelling stops after they go into the field. This time no positive reactions anymore neihter negative. This make me think twice before spending my money.

I think you voiced your experience very close to my thoughts about it.

Dick.