loooooooooooooooooonnnnggg lens recommendations?

[c4-contemporary-art]

Okay, it's time for the good folks to band together and suggest a lens for me.

Here's what I need to do. I want to make a photograph of the sun. I'll

probably use a rollfilm back. For now, a telescope is RIGHT out. I'd like to use

a lens of 600mm PLUS F.L. - now I've seen G-clarons and Apo-artars and stuff

in this F range. But the question is - are they SHARP at infinity focus?? What

is?? According to my calculations, I can't even get close to filling up the

frame of a 35mm neg with a 600mm lens! What am I going to DO???

Suggestions?

 

thank you for your consideration.

Jonathan

[c_p_goerz]

The Artars are sharp at infinity, its a matter of finding a lens you can afford as above 24" they do tend to get expensive for the most part. Have you considered using a slightly finer grain of film(since you are shooting the brightest thing we have to look at) and just cropping in?

 

 

CP Goerz.

[stephen hazelton]

You say a telescope is RIGHT out. But looks to me like any lens that would do what you wanted would cost more than the telescope.

 

What camera is this going on, by the way? How much bellows extension do you have?

 

You might check into a pinhole arrangement. Exposure times are very short due to extreme lighting.

 

You can get some sizable telephoto lenses for MF- for Pentax 6x7, for example- which might come closest to what you want to do.

 

And you might just try 35mm with 500 or 600 + 2x teleconverter. You can use the slowest film, optimum aperture, etc.

[neal_wydra1]

Dear Jonathan,

 

If it is cost that eliminates a telescope, consider contacting a local astronomy club. You may run into a member who has already done just what you are looking for and might be willing to let you tag along and make some expsoures.

 

Neal Wydra

[stephen hazelton]

One of the challenges here is that the image size of the sun is dependent on the focal length, not the film size. Not sure about the sun, but even at 1000mm, the moon is still not a full frame on 35mm. So you are looking for something like 2000-3000mm lens to get a decent size image onto MF film. The telephoto-type lenses for LF don't collapse focal length that much, due to restrictions in the physical size of the lens unit. And a simple lens of that focal length would require a camera 10' long. (That's been done with pipe and a pinhole, by the way.)

 

So far as I know, most of the telescopes that are set up for camera attachment use a T-mount adaptor, intended mainly for 35mm cameras.

[c4-contemporary-art]

thanks for the responses thus far... I don't know. Maybe the pinhole idea

isn't SO bad - but I'm guessing that once I do the number crunching for the

diffraction characteristics - that it's going to be WAY too fuzzy. I was

originally thinking of shooting with something along the lines of a 1200mm

process lens that happens to be functionally corrected at infinity mounted

on my sinar x - then exposed on 6x6 neg on a rollfilm back. Racking out to

10 ft. isn't actually a huge problem - if I need to do that. A retrofocus lens

isn't even important.

 

A telescope would be cost-prohibitive. Any decent 'scope STARTS at about

$5K. (takahashi, astro-physics, etc...) - I wouldn't need an equatorial mount

for such a short exposure - but getting the image out of the scope and onto

the film plane would require a whole nother optical and mechanical

assembly that would make things very complicated.

 

I'm just trying (ambitiously) to make the most detailed photograph of the

sun ever recorded by an amateur (ambitious, yes I know). But check this link

out. This was my inspiration...

 

http://www.astrosurf.com/re/sun_20031029_moon_20031108_mosaic.jp

g

[daniel_smith6]

Why the fixation on sharp lenses, the sun sure isn't sharp?

[photo_color]

I don't intend to cloud up your sunny aspirations, but knowing some folks who do shoot pics of the sun, if your intention is to take one of the best photos of the sun done by an 'amateur', then you may want to rethink the large format idea. Getting really high resolution pics requires specialized equipment - and it has already been done before, by many 'amateur' astronomers. You will need a telescope or a very espensive telephoto for 35mm or medium format - just as costly as the APs, Televues, and Takahashi's, or various brands of other types of high resolution scopes - like Questar Maksutovs or scopes specifically made for viewing and photographing the sun (like those made by Coronado).

 

You need a flat film plane, so forget large format period, because the roll-film backs for large format aren't very flat, not to mention sheet film unless you use a special film holder (vacuum or other). There are, or were large format cameras (4x5 I think) specifically for 'astro' use, and may hold sheet film flatter than usual or may take glass plates.

 

Also you'll need a filter in front of your lens - either a 'white' light type, or a special one for viewing more than just sunpots. Also, if the image is really at a large scale, it's likely to be just dim enough (due to the large magnification) to require tracking the sun for the sharpest image. That means a special mounting for the scope/camera-lens.

 

You are talking thousands of bucks for any set-up that will get you near getting the sharpest photo taken by an amateur. However if you want the sharpest photo taken by an amateur large format photographer, then just have some fun with the pinhole idea, or renting a long focal length lens. You need to be careful not to burn the lens (if any of the elements are cemented watch out big time), the film, the groundglass, or your eye, if unfiltered before the lens. I would approach your project with a great deal of care.

Dan

[c4-contemporary-art]

Okay - thanks for the responses. I will ignore the last one, esp. the

comments about 'burning the glass' (perhaps I'd heat up the darkslide a bit -

at best).

 

My actual objectives are not important and people here seem to be fixated

too much on this. Let me rephrase the question. What is the longest lens

which has great performance at infinity. I am willing to make certain

tradeoffs. i.e. a 600mm lens that can project 80lp/mm to film would be

preferable to a 1200mm lens that can project only 25lp/mm.

 

Suggestions?

thanks.

[photo_color]

Yes, do please esp. ignore the comment about burning, as I got carried away, and what I said applies mainly to human eyes at the eyepiece of a telescope. As to the other comments, yes please ignore them too, because you apparently know more than amateur and professionals who specialize in photographing the sun. Good luck in your pursuit.

Dan

[c4-contemporary-art]

Sorry - Dan - I DO owe you an apology - maybe it was a bit disimissive of me -

but I just thought your points weren't all that strong and aimed more to

'rain on my parade'... here's why I thought that;

 

>Getting really high resolution pics requires specialized equipment - and it

>has already been done before, by many 'amateur' astronomers. You will

>need a telescope or a very espensive telephoto for 35mm or medium

>format - just as costly as the APs, Televues, and Takahashi's, or various

>brands of other types of high resolution scopes - like Questar Maksutovs or

>scopes specifically made for viewing and photographing the sun (like

>those made by Coronado).

 

Getting something with a long enough focal length should be my only real

concern - I think my equipment will suffice for the rest of it. It IS a

specialized task - but no more so than a very specific landscape - or a

portrait. Something within the realm of photographic possibilities. ..

 

>You need a flat film plane, so forget large format period

 

It seems to me that I'd need to stop down QUITE a lot to get my pic

anyway... using something called 'depth of field' - that doesn't JUST apply

at the subject end of things, you know...

 

>Also you'll need a filter in front of your lens - either a 'white' light type, or a

>special one for viewing more than just sunpots. Also, if the image is really

>at a large scale, it's likely to be just dim enough (due to the large

>magnification) to require tracking the sun for the sharpest image. That

>means a special mounting for the scope/camera-lens.

 

Why would I need an ND filter?? I was just planning on stopping down

anyway - and use a very short shutter speed (though I have to admit I'll have

to be very careful with shutter vibration at this magnification...

 

>You are talking thousands of bucks for any set-up that will get you near

>getting the sharpest photo taken by an amateur. However if you want the

>sharpest photo taken by an amateur large format photographer, then just

>have some fun with the pinhole idea, or renting a long focal length lens.

 

It seems to me I shouldn't have any problems if I can find a well-designed

super long focal length lens on my sinar kit w/2 tripods - I can use as many

bellows as required to get the extension I need.

 

Anyway... I REALLY did not mean for this to get so complicated. I simply

wanted to end up with a VERY detailed mural (about 8'x8' size photo of the

sun with minimal grain.

[ole_tjugen]

With a looooong lens, you will have to do some very careful planning to get a picture of the sun at all: It moves. You'll have to aim the camera at exactly the spot where the sun will be when you're all set up and ready to shoot, which is not at all an easy job without some kind of tracking.

 

To get reasonable exposure times (between 1/25 and 1/500 sec, since few LF lenses are faster and the sun will move visibly if the exposure time is much slower), you WILL need ND filters. The alternative is stopping down so far that you might as well use a pinhole!

 

But getting sharp pictures of the sun with LF is quite possible, you just have to decide how sharp you want, and how big a negative to use.

 

Here's one of my attempts - 360mm lens, 9x12cm film, no tracking, sun (and moon) moving at their regular speed of 15 degrees/hour:<div></div>

[mark_blackman1]

Rather than photograph the sun directly, why not project an image onto a pure white, flat surface and photograph that? Use your LF camera's rise/shift to ensure you get the image full on.

[jim_galvin]

The sun (and by coincidence, the moon) is 1/2 degree in diameter. So with a 1000 mm lens, the image is 8.7 mm diameter. So you need a VERY long lens! Telescopes are available for less than $5K, an 8 inch Meade or Celestron for less than $2k, with tracking.

Burning things, the inside of the telescope, the camera, the film, AND YOUR EYES, is a very real problem. Do an internet search on solar photography.

By the way, atmospheric instability (the kind that makes "heat waves" and the stars twinkle) may blur your photo, unless you are at high altitude.