Long lenses for Moon exposures

Again, shutterspeeds in the 15 seconds region at f/8 are way too long, and will result in an overexposure of about 5 stops. It may be dark here, but the moon is basking in full sunlight.<br><br>And assembling a compound camera is not quite impossible. ;-)

<blockquote>

<p>the largest would be an 800mm</p>

</blockquote>

<p>Nikkor-Tele 1200 is the longest LF lens (that I know). Roughly 360mm in 35mm terms, requires bellows draw of at least 750mm.<br>

It doesn't meet the criteria of the OP. I just wanted to mention it.</p>

<p>According to Ansel Adams, the moon has a brightness of 250 cps. It sits behind the sky, therefore you need to measure the brightness of the sky next to the moon and add 250. As the sky becomes darker, the moon will separate from the sky. If the sky is 200 cps, the moon will be 450 cps; about 1 f/stop difference. If the sky is 50 cps, the moon will be 300 cps about 2 1/2 f/stop difference. If you want to photograph the moon as a bright object with some detail, the last example would have an exposure of 1/50 sec @ the square root of the ISO of your film. The sky would be middle grey and the moon would be shinning and depending upon the size of the moon it should have some detail, not empty white.<br>

To Richard,<br>

A 4 inch lens (100mm) regardless of format will render an object when focused at infinite the same size on the film plane. If you want to double the size, you must double the drawing power of the lens (8 inch lens; 200mm). <br>

What changes in the various formats is the angle of view. A 100mm lens on a 35mm camera will see much less than a 100mm lens on a 4X5 camera; one is a long lens and the other is a wide angle lens. But the objects that are seen on the film plane will be the same size if you were to measure them with a ruler.</p>

<p>Paul</p>

<p>Have you considered a telescope with a camera adapter`?</p>

 

<p>OK, my 2cents here.<br>

first, to answer the question. The 15" tele-raptar f5.6 can usually be found inexpensively. Similar tele-xenars and tele artons as well. Also, the 16" or 19" Goerz Artar will will come up relatively inexpensively in a barrel. Fuji and Nikon made longer tele lenses, but they tend to fetch a premium.</p>

<p>Second, let me throw some sense into the mix. There are no inexpensive/normally feasible ways to get a good size image of the moon on a 4x5 sheet of film with your equipment. I really dont want to go into the details.</p>

<p> </p>

Yes, I figured a telescope with an adapter.

 

After a short fruitless search for one I realized it would be pretty pointless without a shutter.

 

 

I think my best option now is to take with a DSLR and a long reflector lens, and just have it burned to film. I don't want it to

fill a 4x5 sheet. Just large enough on 6x6 or 4x5 to see some texture and a little detail.

 

Thanks for the help, patience, and insight.

 

Drew's rube goldberg idea may work too. I will play with that.

<p>Ansel Adams's <em>Moon & Half Dome</em> was taken with a Hasselblad [6X6] and a 250mm lens. It has texture and detail, any lens greater than 250mm will have more.<br>

Paul</p>

<p>There are a number of photos taken with a Nikon 600mm f4 and a couple of 2x converters on the back. Pretty sure there was a thread here on P'net about that in the last couple of years.</p>

<p>We have many hundreds of lunar images, taken with various lenses and cameras.</p>

<p>The longest lens would be the 3 1/2" Questar telescope, with a focal length of about 1300mm.</p>

<p>It yields an image of the lunar disc about 12mm in diameter, about half the height of a 35mm frame.</p>

<p>- Leigh</p>

 

<p>The way I see it put simply is...A 600mm focal length mirror lens on an APSC sensor renders a moon this size in relation to the frame...</p><div></div>

<p>Therefore a 600mm focal length lens on a 4x5 frame will look something like this.....as stated before, the lens doesn't know what area of film is behind it...</p>

<p>600mm on 4x5 just produces more negative space like this....</p><div></div>

<p>Richard: I lashed together a telescope and a 4x5 many years ago. I used an Ilex #3 shutter taken from an Ocilloscope lens. These lenses come up for auction from time-to-time and are relaativly cheap, though the fastest shutter speed is 1/50 th.</p>

<p>A few years ago I took some nice photos of the moon with a 1900mm FL telescope, though I was using a 35mm camera to do it. Try a fine grained film like Ilford Pan-F in a 35mm camera and attach that to a telescope. The adapter to attach a 35mm camera to a scope is not that expensive (like $30 or less) and if this is a one shot project your local astronomy club may have a loaner scope or someone with a scope you can use. <br>

(The scope I used was a Meade 127mm ETX Mac-Cass telescope, but I no longer own it)<br>

Be warned that many dobsonian telescopes may not have enough back focus to put a camera on them. </p>

<p> </p>

<p>Focal lengths (Celestron or Mead)<br>

6500mm = Celestron 16 2" or 52mm image diameter of full moon or sun<br>

4,000mm = 1.26" or 32mm<br>

2,000mm = 5/8" or 16mm<br>

1,000mm = 5/16" or 8mm<br>

500mmmm = 5/32" or 4mm<br>

A standard Celestron or Meade 8" has a focal length of 2,000mm (a tad less than 80") a full moon or sun (only with a SUN FILTER!) will just barely fill a 35mm frame without spilling over. When I was VP of Celestron I used to shoot with our 16" telescope on my SL66 and it would give me a moon of just a bit over 2" on 120 triX.</p>

<p>Full moon, ASA/ISO 400 f11 @ 400/500 sec<br>

1/2 moon f11 @ 250<br>

1/4 moon f11 @125<br>

1/8 moon f11 @ 60<br>

It is a very flat subject so a decrease in exposure and an increase in development will help.</p>

<p>Lynn</p>