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primus96
Joined: 13 Nov 2003 Posts: 225 Location: Yorkshire, United Kingdom
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Posted: Sat Nov 29, 2003 10:22 am Post subject: |
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Is it true that the Aero Ektar lenses are only corrected for the red end of the spectrum.
That is understandable as with black and white film you want haze penetration when making aerial photographs.
How well do they function when used in normal photograhy - especially with colour film. |
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Dan Fromm
Joined: 14 May 2001 Posts: 2120 Location: New Jersey
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Posted: Sat Nov 29, 2003 5:05 pm Post subject: |
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On 2003-11-29 02:22, primus96 wrote:
Is it true that the Aero Ektar lenses are only corrected for the red end of the spectrum.
That is understandable as with black and white film you want haze penetration when making aerial photographs.
How well do they function when used in normal photograhy - especially with colour film.
| The Lens Collector's Vade Mecum says they are very sharp. They've been used in many applications, even adapted to Hasselblads. The rear elements are made of thoriated glass, and radiation damage has turned them brown or yellow. There's folklore around to the effect that exposing the lens to bright UV for a while will restore the original clarity. All this news is second hand, I've never used one.
Cheers,
Dan |
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disemjg
Joined: 10 Jan 2002 Posts: 474 Location: Washington, DC
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Posted: Sat Nov 29, 2003 11:38 pm Post subject: |
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Dan: I gather that the reference you cite is a book; what is the ISBN and full title so I can try to get a copy? |
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45PSS
Joined: 28 Sep 2001 Posts: 4081 Location: Mid Peninsula, Ca.
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Posted: Sun Nov 30, 2003 5:47 am Post subject: |
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I'll jump in,
The Lens Collector's Vade Mecum.
www-antiquecameras-net does not have any up for auction on Eba_ at this time, they usually go for $20 a CD copy that requires Adobe reader 3.0 or higher. Covers mostly European lens in depth but gives some basic info on most US made as they were sold in Europe. Adobe reader 3.0 is on the CD.
http://medfmt.8k.com/mf/radioactive.html
This will give you the most info on the Radioactive Glass used in lens manifacture.
I saw a post or two on photo.net from some who did clear up their "HOT" lens to some extent using UV lights.
Chalres
_________________ The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU. |
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primus96
Joined: 13 Nov 2003 Posts: 225 Location: Yorkshire, United Kingdom
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Posted: Sun Nov 30, 2003 8:52 am Post subject: |
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What I would like to know is this lens going to be any good with colour neg & reversal film if I go to the trouble of getting mounted in a lens board?
There must be some people out there who have at least tried one.
I want a lens where I can use the rising front on a speed without vignetting. |
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Dan Fromm
Joined: 14 May 2001 Posts: 2120 Location: New Jersey
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Posted: Sun Nov 30, 2003 2:22 pm Post subject: |
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On 2003-11-30 00:52, primus96 wrote:
What I would like to know is this lens going to be any good with colour neg & reversal film if I go to the trouble of getting mounted in a lens board?
There must be some people out there who have at least tried one.
I want a lens where I can use the rising front on a speed without vignetting.
| These lenses are quite large and hdavy. They don't just mount on a board. Don't rush out to buy one, look at the ones offered on eBay, where they are not uncommon and are often misrepresented. FWIW, I'm a sucker for cheap lenses, and I don't have a 7" AeroEktar yet.
If what you're looking for is an inexpensive and relatively risk-free lens that's longer than normal, just get a used process lens in barrel and don't look back. The least costly are likely to be Ultragons, made by Agfa. Sold as Eskofot Ultragon, Staeble Ultragon, Repromaster, and Helioprint. The focal lengths closest to the AeroEktar's 178 mm are 150 (yes, that's normal for 4x5) and 210 mm. Either size will go on a 4x5 board.
Lastly, you're in the UK. The UK has had a number of fine lens makers whose products seem to be not too hard to find there. Why don't you look for domestic lenses? Come to thinkj of it, Wray and Taylor Hobson made ~7" process lenses, if you must have a 7" lens. The camera won't care where the lens you put on it was made.
Cheers,
Dan |
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Les
Joined: 09 May 2001 Posts: 2682 Location: Detroit, MI
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Posted: Sun Nov 30, 2003 2:45 pm Post subject: |
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While I haven't tried my Aero on color film, I contend there the field of use is narrow.
The lens itself weighs nearly as much as my Crown, it's correct to be sharpest at wide open, therefore if you intend to use the lens stopped down to 8 or more, you're better off with a Symmar or other 6.8 lens as they weight less than half of this beast.
On the other hand its great to use with flash bulbs.
Huge guide numbers! |
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Murray@uptowngallery.org
Joined: 03 Apr 2002 Posts: 164 Location: Holland MI
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Posted: Tue May 29, 2007 5:25 am Post subject: color correction of Aero-Ektar's |
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The claims about color correction only for specific wavelengths seem to be repeated info unsubstantiated by anything other than repeated hearsay.
The Aero Ektar lenses were used with red or yellow filters, and I've heard less frequently of a clear protective filter. They did not need center spot filters like the Metrogons, so they could be used without the filter.
I'm pretty sure Richard Knoppow and maybe Michael Briggs have countered the chromatic claims with reference to the available patents.
I have read (one of) the Aero-Ektar patent(s) but can't remember if it showed multiple wavelengths in the analysis...typically a monochromatic lens design only has data for one wavelength, or a narrow range that is conspicuous. There may also be references to specific light source spectral lines for wavelength.
I have seen documentation-supported responses I think from Richard claiming they were very well color corrected.
The Aero-Ektar glass formula is intimidating...in the 7-element design, if I remember correctly shows there are 6 or 7 different types of glass, evidenced by their indices of refraction and dispersion (as Abbe number). This many types of glass would not likely be necessary for a narrow spectrum lens.
The 7" f/2.5 is probably the only one that can be adapted to fit a 4x5 Speed Graphic front standard. The longer ones are too big. I have a 309 mm f/2.5 that weighs about 11 pounds and is about 6.5" diameter. It is in a barrel minus it's shutter, but the barrel is the same color as the rest, so I can't tell if it's aftermarket or recycled.
The biggest problem after mounting is they don't stop down as far as other LF lenses, to the typical f-numbers used for typical desired LF DOF, like f/22 or 32. They are typically used terrestrially where very narrow DOF is desired.
My 309 mm only spots down to f/16. The 610 mm goes to f/16 but will rotate further and someone stamped a mark for f/22 on the scale.
Press photographer David Burnett may be the most easily found (publicity-wise) example of a 178 mm Aero-Ektar in use. He documented portions of the U.S. presidential campaign that Gore was in with his Aero-Ektar/Speed Graphic combo and a Holga. _________________ Murray |
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rocklaneeast
Joined: 28 Oct 2002 Posts: 18 Location: Newcastle N.E.England
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Discpad
Joined: 25 Jan 2003 Posts: 81 Location: Cherry Hill, New Jersey
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