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Using a telescope as a lense in medium format


cameron_ertman

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Andreas Fieninger once made an extreme telephoto lense for his

camera. His objective was to shoot an extremely compressed image of

the New York skyline. I am also interested in compressed effects. I

know that there are adapters for hooking 35mm cameras to telescopes,

and spotting scopes. Is there any such adapter for medium format

cameras? I use Hasselblad equipment, and mainly, black and white

film. Thank you in advance for any help!

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Some telescopes can be adapted for use on cameras, but they generally do not give very good results--they cannot be stopped down, and, of course, they do not have shutters, which, unless you have a focal-plane model, would be a serious problem. You would be *much* better off with a telephoto lens made specifically for the Hasselblad, as expensive as it might be.

 

If you are determined, check out the ads in amateur astronomy magazines, such as Sky & Telescope. They might help you track down a suitable adapter.

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I looked into this several years ago for my Pentax 6x7. I called a number of refractor telescope producers and they said that the image circle was too small to fill the frame, that is unless I was interested in their 5 inch model and that was super expensive. I also looked into using the famous Ritchey-Chretien Cassegrain, with its two aspherical mirrors. It can be done, but again, very expensive. I have seen pictures shot with both Celestron Schmidts and large refractors using the Pentax 67 but no other MF camera. Meade and Celestron might be good places to start looking/calling. SR
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Several ways to do this, but not great results unless great effort and some expense are applied. Hasselblad adapters are available at a pricey cost and you wait if not in stock. Most small telescopes adapt readily to 35mm, but MF would require a 2 inch focus tube to even get close to covering the format. It'$ not unusual to find 2" or 4" diameter adapters for MF cameras on telescopes, however. www.lumicon.com and others offer adapters at $300 US to start. I've seen AstroPhysics out of Rockford IL offer adapters for Hasselblad at under $1000 to fit their beautifully made astrographs. Pentax 67 adapters usually are less, why - I don't know. Properly made telescopes do image astronomical objects nicely, whereas photographic telephotos usually are expected to have higher resolution and contrast because we are dealing with film versus human eye. Usually astronomers are using MF cameras to get more image on bigger film compared to 35mm. Working with multiple 6x7cm or 6x6cm images of the same object photographed over time are then sandwiched and printed. Gonzo resolution and color! For your skyline idea, I'm not so sure a telescope would be a good choice. But then, I'm sure you've thought of trying a more conventional approach and then scrunched in Photoshop or something?
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Lumicon solds adapter for Hasselblad (and some other MF) to fit on their giant easy-guider, which mounts on 11 and 14 inches telescopes (Meade or Celestron).

Most users in astronomy use Pentax 6x7 because it is inexpensive, has a shutter (mechanical as far as I know) and therefore adaptators exist.

 

With a small diameter of focusing unit, (like 8 inches telescopes ) you will not cover all the frame of 6x6. Spotting scopes will give a center round.

If you use reflectors like the Schmidt Cassegrain I mentionned, you also will have to operate with a field flattener.

 

That said, I find hard enough to have clear pictures with a 350 mm and 2x converter (long exposures, vibrations ...) to avoid telescopes for conventionnal pictures.

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  • 1 year later...

<body>

This question interested me also and specially for medium format. I

made some tests with spotting scopes in 35 mm and the results where disappointing:

vignetting, very soft image and low contrast. But I think I found a nice

refractor for medium format: The Takahashi FSQ-106. It's a 530 mm f5 four

elements (2 made out of fluorite) and with built in field flatterer. It

has a 4" focuser and can even illuminate a 4x5 with some vignetting. I

hadn't the possibility to try it now, but all reports from many high demanding

astrophotographer agree about the excellent optic. I also think it's the

only affordable (<10'000$) and transportable (<30 kg) telescope capable

for 6x7 without vignetting. The FSQ is about 3'500$ and weight 6 kg.

<p>Here a few interesting info about the scope:

<p><a href="http://www.skypub.com/resources/testreports/telescopes/0004takfsq.html">Test

review</a> from Sky & Telescope

<p>Info at Anacorte <a href="http://www.buytelescopes.com/product_details.asp?pNumber=1971#moreInfo">here</a>

and <a href="http://63.169.124.2/Takahashi/takahashi_fsq_106.htm">here</a>.

<p>Special adapter exist from Takahashi for the Pentax P67II.

<p>Colin

<br> 

</body>

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Thank you for the responses. In the end, I went with a used Hasselblad 500mm APO, and a couple of converters. I can get a fairly extreme telephoto effect when I combine the 500mm with the 1.4X plus the 2X converter from Hasselblad (I end up with a 1400mm F22 lens). This is quite a slow combination; however, I can offset that speed with faster film.
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I wonder if it might not be better to use a large format lens on a custom barrel with a bellows (maybe something like a Novoflex, which has ready made adapters for the camera end, and a screw mount at the lens end) for focusing for this purpose--something like the Nikkor 1200mm T-ED or even a big process lens (Goerz Artars go up to 42" I think)--rather than piling up teleconverters.
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David, I would imagine that the quality would be better with that combination; however, it's going to end up pretty long. One thing nice about the APO lens is that it has internal focusing so that the length of the lens remains constant throughout its focusing range. The lens also has a tripod mount which allowed me to make a special, solid plate that attaches to the lens, and camera making the whole outfit quite solid. You could definitely get a longer lens by going with the other outfit, which would make for some interesting super tele-effects.
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If you want to reach ultra long tele, you can also use a good (or very good) refractor and eyepiece projection,

giving you almost unlimited possibilities. I've seen a picture of the moon taken with the Takahashi FSQ-106 and

eyepiece projection (also special eyepiece from Takahashi) made with a pentax P67. The configuration was

something like 5000 mm f45 and the picture just blows my mind with its sharpness and details, no color shift or

error at the border of the moon. I think with good technique it could give good results for terrestrial use. A 5000

mm must give some interesting flat perspective.

 

Colin

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I have an antique Zeiss wide-field refractor (off the top of my head:

a 1000 mm f8) and have played around with an 18" Wray process lens on

a cardboard tube. The Zeiss is better for eyepeice projection, in

which the lens is essentially only used on-axis where it is

diffraction limited wide-open and, despite its age, is well-corrected

for longitudinal colour. When used in prime focus (i.e. no eyepiece)

the process lens is much better because it has a flat field.

 

I would expect the same relationship between process lenses and

astronomical objectives to hold true with modern lenses since their

design parameters haven't changed much. You can get an excellent long

process lens on the used market for a couple of hundred dollars, a

good wide field refractor will cost you at least a couple of thousand,

so the cheapest way into MF long lens work is a process lens on a

drainpipe. Exposures will be long enough that you can use a hat,

lenscap or your Hasselblad's auxiliary shutter to control the

exposure.

 

That said, the telescope has one further advantage in that the tubular

structure is already aligned so that the lenses and the film plane are

all perpendicular to the optic axis - with a homemade jury rig this

can be hard and frustrating to achieve.

 

In practice the camera support is almost as important as the lens. A

good telescope mount or the sort of fluid head used for video work is

better than most photographic heads, which can flex badly with the

large torques created by the long lever arm of the telescope tube.

Cheap solutions with good vibration performance include bean bags or a

wide-diameter PVC pipe with a pair of V-notches cut in the end.

 

Did anyone else see the wonderful photo used in an advert in a recent

Economist? It showed three photographers with monster lenses: one had

a 35 mm with what what I guessed was a Novoflex follow-focus lens; the

second had a Hasselblad with a 500mm; and the third put the others to

shame with a gi-stonking 4x5 camera with what looked like a rocket

launcher on the front.

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  • 11 months later...

I once used a Pentax 67 body coupled with a Borg (a Japanese manufacturer of refractor telescopes for astronomical purposes) 125mm/6.4 ED refractor to shoot the Statue of Liberty from the south side of Manhattan with some interesting results. The combo does need very solid support but it worked surprisingly well in my project. The Borg optics are well-corrected and provide 6X7 cm coverage with little vignetting. Images through the telescope appear upside down, of course. I bought the telescope in Japan for around $2100 new, which is not too bad of a deal considering it now serves as a dual-purpose instrument for me day and night. My Japanese friends have also used Pentax SDHF series ED refractors and astrographs to shoot distant landscapes. Also come to mind are Takahashi FSQ Fluorite refractor (as mentioned above), Takahashi FCT-series refractors and some AstroPhysics APO refractors. The most cost-effective solution appears to be the Borgs though IMHO.

 

Frank Leung

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