#2. "RE: Focus variation at varied distance?" In response to Reply # 1
South Australia, AU
Thank you Joseph, No examples but have trouble nailing the focusing for small birds in trees Tried spot the other day but not sure if that is my best option for small targets at distance? Might have to do some tests, did not realise that the focus area was actually larger at distance, Would spot be a better choice? ....Gary
#3. "RE: Focus variation at varied distance?" In response to Reply # 2
Farmington Hills, US
Spot will not change the AF area or accuracy, it only narrows down the metering area.
Focus area doesn't really change with distance. It's always the same portion of the frame. Obviously the area of the frame covers a larger target area as the focusing distance increases. The point of the previous reply was that the actual area used for focus is larger than the rectangle you see in the viewfinder, so even if you put the rectangle on your subject, the area surrounding the subject is also used in the focus adjustment.
Gary in SE Michigan, USA. Co-organizer of the Southern Michigan Chapter Nikonians membership - My most important photographic investment, after the camera. D4, D800e, D300, D90, F6, FM3a (black), FM2n (chrome) YashicaMat 124, Graflex Speed Graphic 4x5 My Nikonians Gallery & Our Chapter Gallery
#5. "RE: Focus variation at varied distance?" In response to Reply # 2 Wed 10-Jul-13 06:20 AM by JosephK
Seattle, WA, US
>No examples but have trouble nailing the focusing for small >birds in trees
Small birds in trees present two problems. (1) They are small AF targets, which may not fill the AF sensor. (2) Tree branches can get in the way and often have better contrast resulting in the camera picking the wrong object to focus on. Been there, done that.
>Might have to do some tests, did not realize that the focus >area was actually larger at distance,
Not larger at a distance, just larger than the square in the viewfinder. Normally this is not a problem, but when you are trying to shoot around tree branches....
Single-point AF is probably the one you are looking for. Using the af-on button may help you.
---------+---------+---------+---------+---------+ Joseph K Seattle, WA, USA
#7. "RE: Focus variation at varied distance?" In response to Reply # 0
What lens are your using? I would try one or a number of the following: Stop it down a little to gain a little bit more DOF Try to focus on something a little larger that you know is close to the same distance Check with DOF prevue. Try this with manual focus. Or while on manual focus check the distance markings on the lens and set to just short of infinity. Check again, small objects at intermediate distances can be a little tricky with a shallow DOF.
#8. "RE: Focus variation at varied distance?" In response to Reply # 7
South Australia, AU
Hi Michael, Using an AF-S 300 f4, Been trying some different options to maintain a higher shutter speed Recent trials have been with shutter priority, I'm thinking that I might just have to bump up the ISO to get a "better" DOF Will try out your suggestions, ....Gary
#9. "RE: Focus variation at varied distance?" In response to Reply # 8
Before you sacrifice ISO to increase DOF, be realistic in terms of expectations. With small distant moving subjects, AF is challenging takes practice. Even with the newer AF system of the D4/D800, and a larger subject, 65% success is reasonable.
I've recently used the 300 f/4 and D800E for photos of gulls and pelagic birds on the ocean. AF success is remarkably low even and the misses are large enough that a stop or two more in DOF won't matter.
Do keep the shutter speed high - 1/1000 sec or more. I'd suggest an aperture slightly stopped down - but not beyond f/5.6. Use the center AF sensor only. Try to track and follow the subject if its flying. Otherwise consider other tools and techniques to increase stability.