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I'm technically a beginner when it comes to anything other than point and shoot photography so I apologise if I don't explain myself clearly.

I have a Pentax Q with an 85-200mm K lens, I'm using a Q to K mount.

I've only tested it once on the moon but I couldn't seem to get a clear image of it. I set my metering to the center to it removed the "glow" from the moon and you could see the detail but no matter what I couldn't quite focus onto it properly.

Adjusting the focus only brings the moon into focus so much.

Are there any tips or tricks I'm missing that can help me achieve this? I've read a few posts about moon photography but I'm wondering if there's anything wrong with my equipment in this case that's stopping me from achieving a clear image?

*****EXAMPLE SHOT*****

enter image description here

Thanks.

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    \$\begingroup\$ Could you post a couple of examples of photos you've got, along with their shooting parameters? That really helps when trying to diagnose this sort of issue. \$\endgroup\$
    – Philip Kendall ♦
    Jul 15, 2014 at 11:06
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    \$\begingroup\$ @PhilipKendall I will post an example shot when I get home from work \$\endgroup\$
    – SaturnsEye
    Jul 15, 2014 at 11:11
  • \$\begingroup\$ what do you mean by "Adjusting the focus only get the moon into focus so much."? also i'll join @Phillip in his request from you to put couple of pics that you took \$\endgroup\$
    – K''
    Jul 15, 2014 at 16:07
  • \$\begingroup\$ @akram Sorry, not the best explanation! basically when adjust my focus on the lens, it's either blurred, or really blurred. I can't seem to focus enough to get the moon clear. \$\endgroup\$
    – SaturnsEye
    Jul 15, 2014 at 16:09
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    \$\begingroup\$ Please don't edit your question to include an answer. It defeats the purpose of the site. If someone else has answered your question, mark that answers as accepted. That, in turn, marks the question as "solved". If none of the answers are completely correct, feel free to add and accept a new answer of your own. \$\endgroup\$
    – mattdm
    Jul 16, 2014 at 6:16

2 Answers 2

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The moon is way, way farther away than the hyperfocal distance of your lens. This means that if you focus at the hyperfocal distance, everything between half that distance and infinity should be in focus.

If you just focused at infinity, the moon should be in focus, because it's really far away.

However, although the moon is in focus, your optics are not going to perfect, and the atmosphere is going to add a noticeable glow to moon, depending on the amount of smog etc. there. "Seeing" - atmospheric turbulence affecting optical performance - is also going to unsharpen your image.

So:

  • Focus on infinity
  • Use an aperture ~ f/5.6-8
  • If you can, stabilize your lens with something
  • Take a number of pictures and then stack them together to help eliminate the effects of bad seeing.
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  • \$\begingroup\$ How do I focus to infinity? I've heard this term and understand it but how do I achieve it exactly? \$\endgroup\$
    – SaturnsEye
    Jul 15, 2014 at 15:55
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    \$\begingroup\$ To focus at infinity you set your lens to the infinity symbol. Since you're using a zoom lens it may be that infinity is only shown for one focal length (or not at all). Here's a link with some pics: markushartel.com/blog/learn-from-markus/… \$\endgroup\$
    – moorej
    Jul 15, 2014 at 16:59
  • \$\begingroup\$ Hmm ok, so can the the aperture setting affect the focusing at all? to get most out of using aperture setting is it best to do all my shooting with manual setting and not leave anything on auto? \$\endgroup\$
    – SaturnsEye
    Jul 15, 2014 at 18:04
  • \$\begingroup\$ I went back this morning and looked at the moon and realised that my camera actually goes past infinity and it's such a slight turn back of the focus that I never realised the first time and I've actually got the moon in focus now! Thanks for all your help. \$\endgroup\$
    – SaturnsEye
    Jul 16, 2014 at 3:25
  • \$\begingroup\$ @SaturnsEye yes, most lenses when you slam the focus ring to the far end are NOT at infinity. It needs careful fiddling. I've found that an angle viewfinder (to make it more convenient to look at the focusing screen when the camera is pointing up) with magnifying function (so you can show the moon in more detail) work to make things a lot easier). \$\endgroup\$
    – jwenting
    Jul 16, 2014 at 10:28
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I suspect this may be a case of pushing the equipment a little bit too far - assuming you've got the Q7 with the larger sensor (things get even more extreme for the original smaller sensored Q), you're looking at an 35mm equivalent focal length of 200 x 4.7 = 940mm, which is a pretty long lens. From what I can find on the web, the Q has "only" 4x zoom when doing manual focus, which is going to make getting a really accurate focus at 940mm pretty tricky - I struggle with 10x zoom at 400mm equivalent.

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  • \$\begingroup\$ Most of what you have said just went straight over my head, sorry. Like I said in my post, I'm basically a beginner when it comes to the technicalities. Are you saying it's not possible to get a clear shot with the Q and my lens? would it be possible with a 100mm lens and cropping the image afterwards? \$\endgroup\$
    – SaturnsEye
    Jul 15, 2014 at 11:12

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