rollin

this will help I think :

http://www.photozone.de/3Technology/demos/DOFbutton.htm

Rollin

I use a G1548 with Arca swiss B1g for every subject, and I use it for all my pictures.

Often it is overkill, but I invested a lot in glass so I don't want to have unsharp images because I don't want to carry a good tripod.

A 600mm f4 on a 13xx? I was in a well known zoo in Germany last week and I was able to compare at least 7 different combinations of tripods and heads, all with 500 f4's and 600 f4's. Only one body was unmovable. Mine.

Others had very good heads (heavy linhofs eg) and not the head moved but the legs, and this was a Gitzo CF 13xx. Others had a G1548 with a louzy head. I'm not saying you don't get good pictures with it. I'm just saying I want sharp pictures in every condition, no matter what glass I put on it. And although I plan my trips and subjects, I often end up doing something else.

Just my 0.02 �

Rollin

I'm certain Jan means the common buzzard Buteo buteo, which is quiet common in this area and which is known to eat carrion most of the time, especially in winter. One can say it is the local vulture apart from the crows and magpies. All the talk about this species without knowing it.... Strange.

Jan, just choose a nice calm spot in the fields with a faraway bakground, ask permission to the owner to set a small hide somewhere near some bushes, start feeding and after a while the local buzzard(s) will come feeding on it. It can take some weeks, but it will work. I've been there, trust me.

Rollin<div></div>

How can a SU-4 replace a SC17 ? If you have only one flash ?

Nope, I'm afraid it will be the second hand Sc17 at the end.

Rollin

Hello Jan,

Of course this doesn't harm these birds. And of course one doesn't need to continue feeding. Buzzards, like all creatures have evolved in perfect adaption to their environment. Look at it this way. If a buzzard finds a big dead animal, on which it can feed for a week. Do you think it will stay with the skeleton after this week till it dies from starving?

Rollin

I've done good business with the German company called Isarfoto

http://www.isarfoto.com.

They have everything a wildlife-photographer can ask for, a good service and good pricing.

Rollin

Thanks David.

This discussion is the same as "I noticed I got a bad DOF with my Hassy, I took my sister's APS and... my pictures are much better now". I know, I know, that's not what Edward meant, but I hardly see an advantage in smaller negative sizes, be it chemical or digital. But hey, who am I do take away someone elses joy? If you like digital camera's because of their better DOF (if it is true or not) shoot away and have a good time.

Rollin

No, it didn't. But I guess that's not the issue here. The question is : is the DOF different from the same picture shot with a lens with more mm's?

Rollin

Hmmm, I always thought that subject-size and Dof are related, so if you picture a bird with a 50 mm frame filling, DOF is just the same as with a 500 mm and frame filling. So, if you shoot a bird at 30 feet with a 50 mm and with a 500 mm, and you crop the 50 mm picture till it is the same as the 500(assuming resolution is no issue here) it is quiet possible DOF is the same in both pictures. But other, much smarter photographers can maybe shine a light in this discussion. I am maybe not considering the size of the negative/CCD

This page for example is interesting:

http://www.luminous-landscape.com/dof2.htm

Rollin

Dave,

I make a living picturing bats, and I have some years experience including making flight pictures.

In the previous posts there as a lot of valuable information. Stepan Pylyp is right when he says you have to consider the delay of the whole system. However, when you connect the beam to the flash the delay is normally very short, in the neighbourhood of 1 ms.

The choice of your flash is important but I see you have good material. The Nikon SB28 is perfectly capable of "freezing" the bats motion, if you set it in M- mode on 1/8th power. This gives a flash duration time of 1/2500 s. That should be enough. Metz flashes are also a good choice, if you can shorten the flash times. The 45CT 3 or 4 are very cheap now and capable of giving very short bursts of light.

All these flashes work with the very normal and cheap flash cables with those small round contacts. They cost 1$ or so.

I don't know anything about Woods' systems. They look allright but too expensive for me and someone made a system that fulfilled my requirements better. It is a two-beam system, so you can make a cross or whatever to make sure the bat is in the middle of the image when the flash goes off. Also, one neam has to be crossed before the other one, so my film is nit filled with the bats' backs (make sure you connect the beams in the right order, or you only have the backs !!!)

If your system works on the flashes that means that your shutter of your F90x must be open all the time, at least till a bat has passed the beam. So, you must work in a very dark environment. Robert Kennedy stated that you have to choose your location very carefully. He is right, most bats are quiet easily disturbed. When you know a good roost ( let's say a cave) you better work very slowly. You first set your equipment (or dummy equipment) and see how the bats react. Then, you make your pictures for only one or two hours and you DO NOT enter the roost at the same time. This will be too much for the animals. Also, AVOID making pictures in the period they have young, between May and August. After that the youngsters can fly and if disturbed the problem is not too big (but still).

Somenone mentioned picturing them when hunting, above water for example. Well, let me state first that almost all pictures of flying bats in environment are made in a studio. Merlin Tuttle, Dietmar Nill, Stephen Dalton all have studio's where they picture not all but a great deal of their bats. I do not say these are caught, most of the time these are sick animals that are kept in captivity for a short time. So these beautifull images are not made in the wild, do not forget when you try to do the same !

There are exceptions on this of course. I know some Dutch photographers that picture bats above water when they pass a small bridge. They put some food on a stick that is just under water so the bats are trained to pass the bridge at the same point.

Almost the same trick was used by mister Dalton, but he used a device with compressed air to shoot prey vertically and trained some Horseshoe bats to collect the food. Indeen, in wild conditions. These pictures are amazing, but I don't have to tell you the difficulty of this project.

Normally I'm able to get a 50% success with normal flight pictures in dark conditions, wich is very (!) high. Very stunning pictures are let's say made in 5% of the case. Also not bad.

To end with, Vesa also made some good comments, but if you want to picture bats in the wild and in their environment, make it a lifetime project. This is very very hard. You can't work on the flashes anymore, and you don't know where the bats are flying. Your best chance I guess will be an electronical one, with a series of beams measuring the speed of the animal and giving your shutter a signal at just the right time. But you should better contact the MIT if you want to do this (a friend of mine is considering a small radar to do the trick...).

Oh, one last thing. Vesa said he has to overexpose his film with 1 stop. This is called the reciprocity failure, typical with fast or slow speeds. I think you will find more of this in other posts.

E-mail me if you have more questions about this.

Rollin <rollin@natuurfotografie.be>

I've had the problems described by Art with my B1G. I made it a habit not to tighten in up. It is never stuck now.

When it became dirty, I sent it in and they cleaned it under warranty within the week.

It seems to me that the problems with service are local. The problem of getting dirty is a pain, and I regret one cannot open the ball-head and clean it like it should be done: in parts. I made a cover for it so I can use the head with the cover on it and I've had no problems ever since.

Rollin