Focal lengh to capture the moon

[Cunha]

Hi,

I need to photograph the moon in a way that occupies most of my 35mm FF frame without crop. Or bigger than the frame. I need a clear full moon with craters (no problem).

The image will be in portrait mode.

My test using a Canon EF 100mm macro L lens resulted in a very small image for my needs (image attached).

What lens do you suggest to produce a big image of the full moon?

Thank you very much.

[Waddizzle]

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@jrhoffman75 wrote:
Buy cheap buy twice.

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'True, but it was relatively inexpensive.  I have yet to buy a replacement.  In fact, I have since purchased a fitting for to use an eyepiece with it.  Now I have a "telescope" to use.

[ebiggs1]

"Now I have a "telescope" to use."

Good money after bad?  Glad it's you. not me.

[Waddizzle]

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@ebiggs1 wrote:

"Now I have a "telescope" to use."

Good money after bad?  Glad it's you. not me.

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Whatever you say, guy. 

No one asked you to buy it, which makes your coments sound rather snobbish. I am satisfied with it.  The little kids love looking thourgh it.  Once again, you have demonstrated you have no idea what you're talking about half the time.

[ebiggs1]

"... you have no idea what you're talking about half the time"

Thanx!  I thought it was more like only 10% of the time.  But it's early.

[TCampbell]

Here's a link to one of my moon images.  This was shot using an APS-C sensor camera (Canon 60Da) while attached to a TeleVue NP101is apochromatic telescope (quad element APO).  The telescope is a 101mm aperture f/5.4 scope (540mm focal length) but I used a TeleVue 2x powermate (it's like a 2x tele-extender but very high quality.)  That turns the scope into a 1080mm f/11 lens.

https://flic.kr/p/CFgcVf

This image is cropped in... but only very slightly (it was off-center in the original image and I cropped it to center -- it wasn't a strong crop.)  I have never tried using my 4x powermate to shoot the moon (that'd take me to 2160mm and f/22)  

If you want to shoot using a full-frame camera and a telescope there are a couple of complications.

1st:  Do not use any telescope that has a Newtonian reflector design unless that design is specifically sold as an "astrograph" (an astrograph is a any telescope primarily designed for imaging rather than visual astronomy.)

2nd:  The method to connect a camera at prime focus (meaning the telescope becomes the camera lens) usually involves using a camera nosepiece that is in two-parts... one part inserts into the eyepiece receiver of the scope and as male t-threads at the back.  The other part is the "t-ring" which has female t-threads and the camera-specific mount (e.g. you'd need an EOS-mount version).  But this wont work for a full-frame camera.

A t-thread has a clear aperture of only about 37mm and you NEED just slightly more than 43mm (44mm would be fine) in order to avoid vignetting on the sensor.  There are wide-opening "prime focus adapters" for Canon mount that do not use t-threads (it's basically one solid machined piece with the 2" diameter barrel and EOS mount all in one).  This will typically provide about 47mm of clear aperture (and anything beyond 44mm is acceptable).

An 8" SCT would be fine (an 8" SCT will typically be an f/10 scope with just over 2000mm focal length).  

Photographing the moon with a telescope is relatively easy.  Photographing anything else will get ... complicated (a bit of a learning curve.)

[Mitsubishiman]

IMHO a great photograph of the full moon is more dependent on conditions, a very expensive camera lens will still be at the mercy of the conditions, one can assume that the best will always be with a "long" lens, or the best will be with a telescope, that is finite thinking and I would normally agree.
The advice of the contributors is spot on, if conditions are optimal, however if conditions are you can get a great shot, and the objection to cropping, well if you want to fill the frame, odds are good you will need to crop, think of it this way, unless you have access to the JPL lab equipment the shot you take will be less than your dream, if you have good conditions even an average lens can pull off a good shot, we all hope and try for perfection, and we settle for the best we can dodo.
This picture was taken with 40 D, 70-300 (cheaper version) tracked out, CP (yes it does help) and cropped.
http://mitsubishiman.deviantart.com/art/Full-Moon-October-2013-408130997

It may not be life changing, but the conditions made it a good photo, that year I went out every full moon for a year, same equipment just different locations and conditions.

http://mitsubishiman.deviantart.com/gallery/41857182/Full-Moons-2013

And now I have a 5 DSr, a 70-200 2.8 L, Manfrotto 190 and conditions still are an issue.

http://mitsubishiman.deviantart.com/art/Cross-Moon-610467197

[Waddizzle]

"IMHO a great photograph of the full moon is more dependent on conditions, a very expensive camera lens will still be at the mercy of the conditions, one can assume that the best will always be with a "long" lens, or the best will be with a telescope, that is finite thinking and I would normally agree." 

Quite true.  One condition that really affects image quality is relative humidity.  My Moon pictures taken when it is humid, like the one I posted earlier, are nowhere near as sharp as photos taken when there is a cooler and drier atmosphere.  Taking shots when the sun is shining through the atmosphere between you and the Moon exhibit reduced sharpness, too.

[TCampbell]

"Seeing" conditions are more important than humidity.  Humidity falls into the category of "transparency".

"Transparency" can be humidity, dust, smog, etc.

But "seeing" refers to the stability of the atmosphere -- which behaves like a lens.  The analogy I'm fond of using is to imagine a coin placed at the bottom of a pool of water.  If nobody is making any waves and the water is still, you can get a clear view of the coin.  If the water is disturbted, then the image of the coin is distorted and wobbly.  

Here's a sample video I recorded of Jupiter (through a 14" SCT):  https://www.youtube.com/watch?v=d5cavIkzOBA

Here's a sample video I recorded of a section of the moon (through the same SCT except the video is produced by something called a 'Stellacam' which only has video out (not a digital camera) so I used an iPhone to show the display on the observatory's monitor:  https://www.youtube.com/watch?v=w681JpMZM8c

But these give you an idea of what you're up against when you're trying to image the moon and why some nights are just better than others.

I've had terribly transparency (extremely humid) and yet tack-sharp "seeing" (everything was exceptionally well-resolved.)  To get a sharp image, it's the "seeing" that needs to be good.

To have good "seeing" conditions then ideally you want:

a)  No Jetstream within 200 miles of your location

b)  No cold-fronts or warm-fronts within 200 miles of your location

c)  Local geography should preferably be "flat" to promote a smooth / laminar airflow

d)  Cool surface conditions (oceans or massive lakes are good) to eliminate thermals.

You can check your "seeing" conditions at a couple of websites.

In North America (I think this website covers locations across the US & Canada) you can use the Clear Dark Sky website:

http://www.cleardarksky.com/csk/

On that website, the primary rows are cloud cover, transparency, seeing, and darkness.  Cloud cover and darkness are fairly self-explanatory.  You'd know if it was cloudy outside just by looking out the window.  But it's the "seeing" row and even the "transparency" row (especially the "seeing" row) that I pay attention to.  The boxes predict the hour-by-hour conditions that are expected.  The darker the box, the better the conditions (white is very bad, dark blue is very good.)

Another (similar) website / resource is the Clear Outside website:

https://clearoutside.com

Clear Outside provides forecasts around the world (not just in North America).  However even though I live in North America (and this is the Canon USA website so expect that's true for most of us) I usually check both websites because sometimes they'll have conflicting forecasts.

[Waddizzle]

I always wonder about shutter speed when photographing the Moon.  Is 1/100 sec fast enough to freeze the motion of the Moon with almost1000mm [600mm x 1.6 = 960mm] of lens staring at it? 

I can watch the Moon drift from the center of the frame to completely out of it in a minute, or so, maybe less.  I've never really timed it, but you can watch it waltz across the Live View screen at pretty steady pace.  It seems fast enough to cause motion blur without sufficient shutter speed, and I am not using Image Stabilization.  Using IS on a tripod is a drain on the battery, and I seem to get sharper pictures of the Moon with it turned off, anyway.

1/100, f/11, ISO 200

I also wonder about the true color of the Moon.  I mostly use "Daylight" white balance with Moon photos, which gives it a tint towards tan.

[kvbarkley]

Luckily the moon is a brightly sunlit object so the sunny 16 rule comes pretty close.