8 X 10 Studio work Recommendations
Frank
shoot oil paintings for reproduction. The publishers want 8X10
transparencies. What camera would you recommend? What lens considering the
paintings sizes are 20"X24" up to 40"X60" and the studio is limited to 18
feet from the paintings to the camera? I've worked with 4X5 and have 2000
watt seconds of flash. I polarize both lights and camera and lose about 2
1/2 stops so I assume I will have to pop the flashes more than once. Any
other help with this type of work appreciated. Thanks
Frank
annqlee
I would get the Toyo 8x10 with a 300 APO Symmar.
Magnification is (v-f)/f and 1/f=1/u+1/v
So at 20x24 that is roughly magnification of .4
so the bellow extension is: 420mm and the distance away is 1050mm.
For a 40x60, it would be 353mm belows and 1989 mm away.
You can go to my diffraction page to see the DOF:
http://carcassi.eng.uci.edu/Eportfolio/technical/diffraction/diffraction.htm
Although it is flat, you should use around f22 just in case. A 2000 joules
pack would
give around f16 or f22 at 10' with umbrella, cut that down 2.5 stops then
you are talking
at least two extra pops...Polaroid! Just watch out for glare.
Good Luck,
Ann
"Frank" <fr...@touchstoneart.com> wrote in message
news:9d9biv$7ss$1...@news.datasync.com...
Richard Knoppow
No suggestions about the camera, nearly any will work. The lens can
be a good enlarging lens or a process lens. Excellent apochromatic
process lenses are a drug on the market now (such as the Goerz Red-Dot
Apo Artar, 19" is the most common FL). Either type will be operating
in about its optimum range for this work. You will need to arange a
shutter of some sort but, since you are using strobe, it doesn't have
to do more than cap the lens.
The formulas for distance are:
Lens to Subject = [1/m + 1]f
Lens to Image = (m + 1)f
Remember that you are making reductions. Given the largest painting
the reduction ratio is about 1/6. For a 19" lens that comes out to be
about 11 feet from lens to painting and about 22 inches bellows draw.
The lens is long enough for the illumination of the image to be pretty
uniform.
You may want to compensate for the bellows draw. The formula is:
Effective stop = vF/f, where F = the marked stop, f = the focal length
and v = lens to film distance.
Or to find the necessary marked stop F = Ef/v where E is the
effective stop.
For the 19" lens above and a 1/6 reduction f/11 is actually about
f/13
You should use an exposure meter to determine the exposure. Watt
seconds can not be translated directly into illumination. It depends
on the flash tube, the efficiency of the reflectors, and some other
factors.
---
Richard Knoppow
Los Angeles, Ca.
dick...@ix.netcom.com
Richard Knoppow
>"Frank" <fr...@touchstoneart.com> wrote:
>
>>I would like some input for doing large format transparencies. I need to
>>shoot oil paintings for reproduction. The publishers want 8X10
>>transparencies. What camera would you recommend? What lens considering the
>>paintings sizes are 20"X24" up to 40"X60" and the studio is limited to 18
>>feet from the paintings to the camera? I've worked with 4X5 and have 2000
>>watt seconds of flash. I polarize both lights and camera and lose about 2
>>1/2 stops so I assume I will have to pop the flashes more than once. Any
>>other help with this type of work appreciated. Thanks
>>
>>
>>Frank
>>
>>
> No suggestions about the camera, nearly any will work. The lens can
>be a good enlarging lens or a process lens. Excellent apochromatic
>process lenses are a drug on the market now (such as the Goerz Red-Dot
>Apo Artar, 19" is the most common FL). Either type will be operating
>in about its optimum range for this work. You will need to arange a
>shutter of some sort but, since you are using strobe, it doesn't have
>to do more than cap the lens.
> The formulas for distance are:
>
>Lens to Subject = [1/m + 1]f
>
>Lens to Image = (m + 1)f
>
Oh, dear! I left out that:
m = magnification
f = focal length of lens.
Remember that the image is smaller than the object so m will be a
fraction.