Photo group?

On Tue, 20 Feb 2007 22:09:23 -0800
"William Graham" wrote:


"donLouis" wrote in message
...
On Tue, 20 Feb 2007 20:01:19 -0800
"William Graham" wrote:

An interesting question....You would have to know how far from the
camera it is....What you are really asking is, "How much angle of
motion is allowed before you perceive a photograph to be out of
focus? And, (I suppose) the answer to this is partially subjective,
since it depends somewhat on the subject....Some amount of blur is
expected when you are taking pictures of fast things......

snip
as to the angle, i want to stick to 90 degrees, i.e., a side
shot of the dragster ( or a funny car) fully in the frame.
the difficulty here is that if both cars are present, i would
like _both_ cars fully in the frame (yeah, right!).
snip

Well, I was talking about the angle created by the motion that takes
place during the time that the shutter is open.....IOW, if you are
only a few feet away from a race car when you take the picture, it
will move perhaps a foot or more while the shutter is open, and will
look very blurred. But if it is 100 feet away from the camera, then
that foot that it moves will only subtend a very small angle on the
film, and it won't look very blurred....that was the angle I meant.
There must be a point where the picture will look sharp for all
angles that are small enough, and I was wondering where that point
is.

technical foul. bummer. it's the wild turkey that blurs my vision
while reading...

from that point of view, the farther away from the dragster, the
closer you get to the optimal point. the first practical limit is
the focal length of the lens. the mathematical limit would be
reached when the tangent of the complementary angle approaches 90
degrees.

operationally, you are not allowed to freely move forward or
backward in the stands, therefore the height of the triangle is
fixed. therein lies the problem (as to shutter speed); at any
given point along the track, a dragsters or funny cars speed
can be very erratic, changing the base of the triangle in ways
that are hard to predict.

although i've never tried it, it is theoretically possible to
buy the same seat at the same track year after year (fixing
the height of the triangle). given a height, and a "probable
range of speeds", it shouldn't be to hard to trig up a shutter
speed that increases the yield of usable images.

william, you're the man. thank you for forcing me to read the
question.

p.s. if my analysis is flawed, please feel free to tell me so.

--
donLouis
papaindia (at) comcast (dot) net

"donLouis" wrote in message
...
On Tue, 20 Feb 2007 22:09:23 -0800
"William Graham" wrote:


"donLouis" wrote in message
...
On Tue, 20 Feb 2007 20:01:19 -0800
"William Graham" wrote:

An interesting question....You would have to know how far from the
camera it is....What you are really asking is, "How much angle of
motion is allowed before you perceive a photograph to be out of
focus? And, (I suppose) the answer to this is partially subjective,
since it depends somewhat on the subject....Some amount of blur is
expected when you are taking pictures of fast things......

snip
as to the angle, i want to stick to 90 degrees, i.e., a side
shot of the dragster ( or a funny car) fully in the frame.
the difficulty here is that if both cars are present, i would
like _both_ cars fully in the frame (yeah, right!).
snip

Well, I was talking about the angle created by the motion that takes
place during the time that the shutter is open.....IOW, if you are
only a few feet away from a race car when you take the picture, it
will move perhaps a foot or more while the shutter is open, and will
look very blurred. But if it is 100 feet away from the camera, then
that foot that it moves will only subtend a very small angle on the
film, and it won't look very blurred....that was the angle I meant.
There must be a point where the picture will look sharp for all
angles that are small enough, and I was wondering where that point
is.

technical foul. bummer. it's the wild turkey that blurs my vision
while reading...

from that point of view, the farther away from the dragster, the
closer you get to the optimal point. the first practical limit is
the focal length of the lens. the mathematical limit would be
reached when the tangent of the complementary angle approaches 90
degrees.

operationally, you are not allowed to freely move forward or
backward in the stands, therefore the height of the triangle is
fixed. therein lies the problem (as to shutter speed); at any
given point along the track, a dragsters or funny cars speed
can be very erratic, changing the base of the triangle in ways
that are hard to predict.

although i've never tried it, it is theoretically possible to
buy the same seat at the same track year after year (fixing
the height of the triangle). given a height, and a "probable
range of speeds", it shouldn't be to hard to trig up a shutter
speed that increases the yield of usable images.

william, you're the man. thank you for forcing me to read the
question.

p.s. if my analysis is flawed, please feel free to tell me so.

Seems good to me....You are right that the greater the distance you are away
from the "action" the better. But, on the other hand, the longer lenses are
slower, so you may have to leave the shutter open so long that the blur is
there anyway....Of course, following the action with the camera always
helps....If you can do this right, you might get a razor sharp image, even
of something moving really fast......

On Wed, 21 Feb 2007 23:37:02 -0800
"William Graham" wrote:


"donLouis" wrote in message
...
On Tue, 20 Feb 2007 22:09:23 -0800
"William Graham" wrote:


snip

although i've never tried it, it is theoretically possible to
buy the same seat at the same track year after year (fixing
the height of the triangle). given a height, and a "probable
range of speeds", it shouldn't be to hard to trig up a shutter
speed that increases the yield of usable images.

william, you're the man. thank you for forcing me to read the
question.

p.s. if my analysis is flawed, please feel free to tell me so.

Seems good to me....You are right that the greater the distance you
are away from the "action" the better. But, on the other hand, the
longer lenses are slower, so you may have to leave the shutter open
so long that the blur is there anyway....Of course, following the
action with the camera always helps....If you can do this right, you
might get a razor sharp image, even of something moving really
fast......


that's the conventional wisdom, to "pan" with the car, blurring the
background, and freezing the car (except the tires). there was
a discussion of this just recently. as far as backing up, the other
operational constraint are the stands, which, at a drag strip, can
be pretty small. ultimately, i need to get down to the local track
with something longer than i currently own...

--
donLouis
papaindia (at) comcast (dot) net

Jim wrote:

There is no newsgroup which isn't full of feuds. People do tend to feel
very strongly about the relative merits of various cameras, etc., anyway.

.... and other stuff.

donLouis wrote:
On 19 Feb 2007 18:40:23 -0800
"Annika1980" wrote:



Let's see .... film is dead, Canon Rules ..... what else would you
like to know?

how about, "what kind of shutter speed would i need to capture
a top-fuel dragster perpendicular to the camera, and at the
990 mark?" ?


Depends on how you want to frame it. Do you want it frozen in time or
blurred to show the action? Or are you panning to freeze the vehicle
against a blurred background?

Either way, the real problem is tripping the shutter at the exact
instant. I'm guessing the "990 mark" is just before it crosses the
finish line?

The other thing is you'd need to be using a fairly wide angle lens to
get the whole thing in while shootin' perpendicular. Most of what I see
are a 3/4 head on shot that uses fore-shortening to get it into the
frame using a moderate tele.

Anyway, something 1/250 to 1/4000 sec should do the trick.

Michael wrote:
"donLouis" wrote in message
...
how about, "what kind of shutter speed would i need to capture
a top-fuel dragster perpendicular to the camera, and at the
990 mark?" ?

--
donLouis

1/500th of a second with a focal plane shutter, 1/1000 with a leaf shutter.



Leaf shutters that do 1/1000 get kinda' pricey; most every one I've ever
seen was limited to 1/500 sec.

Lloyd Wells wrote:
Since I've started killfiling instigators and their respondents, the only
messages I see are from people asking if there's a non-feuding photo group!

Ha!

On Mon, 26 Feb 2007 23:01:54 -0500
Pudentame wrote:

donLouis wrote:
On 19 Feb 2007 18:40:23 -0800
"Annika1980" wrote:



Let's see .... film is dead, Canon Rules ..... what else would you
like to know?

how about, "what kind of shutter speed would i need to capture
a top-fuel dragster perpendicular to the camera, and at the
990 mark?" ?


Depends on how you want to frame it. Do you want it frozen in time or
blurred to show the action? Or are you panning to freeze the vehicle
against a blurred background?

having the car blurred really isn't my taste, so either frozen or
panned is what i'm looking for.

Either way, the real problem is tripping the shutter at the exact
instant. I'm guessing the "990 mark" is just before it crosses the
finish line?

the "990 mark" is 3/4's of the track (990 feet). the official timing
mark is actually at 1000 feet.

The other thing is you'd need to be using a fairly wide angle lens to
get the whole thing in while shootin' perpendicular. Most of what I
see are a 3/4 head on shot that uses fore-shortening to get it into
the frame using a moderate tele.

this is exactly were i lack experience and skill. i've never been
good at "looking and seeing" how far away something is, be it
football, baseball, photography, or anything. i'm much beter with
a tape measure or a distance scale.

i was thinking that i would need longer than 105mm. when you
say "fairly wide", how wide are you thinking? more than 28mm?

--
donLouis
papaindia (at) comcast (dot) net

donLouis wrote:
On Mon, 26 Feb 2007 23:01:54 -0500
Pudentame wrote:



The other thing is you'd need to be using a fairly wide angle lens to
get the whole thing in while shootin' perpendicular. Most of what I
see are a 3/4 head on shot that uses fore-shortening to get it into
the frame using a moderate tele.

this is exactly were i lack experience and skill. i've never been
good at "looking and seeing" how far away something is, be it
football, baseball, photography, or anything. i'm much beter with
a tape measure or a distance scale.

i was thinking that i would need longer than 105mm. when you
say "fairly wide", how wide are you thinking? more than 28mm?


I was thinking you were going to be relatively close to track-side; to
fill the frame with the dragster. I think I saw in one of your later
posts you're going to be farther up in the stands.

Depending on what you're shooting with a couple of good zooms 28 - 70
and 80 - 200 might be a good lens choice, then use the one that gives
you the best frame.

A good monopod might help. I doubt they'll let you take a tripod up in
the stands.

I'd try for a tack-sharp manual focus on the lane at the mark and trip
the shutter 1/250 or faster as the dragster just barely comes into the
frame. That'll make allowance for finger & shutter lag.

Might be a good idea to try out your techniques at a local strip before
tackling the Winternationals or such.

"William Graham" wrote in message
. ..

"donLouis" wrote in message
...
On Tue, 20 Feb 2007 20:01:19 -0800
"William Graham" wrote:


"donLouis" wrote in message
But if it is
100 feet away from the camera, then that foot that it moves will only
subtend a very small angle on the film, and it won't look very
blurred....that was the angle I meant. There must be a point where the
picture will look sharp for all angles that are small enough, and I was
wondering where that point is.

That's impossible. You don't know how bright it's going to
be, so you don't know what aperture it'll call for. Or shutter sp. Or how
far away you'll be forced to stand, so lens length.. And they all create
different DOF. The only thing I would try is to go twice and hope for a few
keepers the second time. Bob Hickey