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Old Nov 13, 2012, 8:15 AM   #1
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Default Milky Way AF Issues

Last night was a perfect night to shoot the milky way. I decided to try my luck, but to no avail.

I put the E-620 with the 14.42mm (3.5-5.6) on the tripod and tried to fire away. The AF wasn't able to get a lock (and fire).

I started off by shutting down the camera and turn it in on to reset the lens. I had it on shutter priority with 20sec. I tried at ISO 100 and ISO 400. I attempted to look through the viewfinder and manually adjust the focus, but I couldn't see anything.

I read a few places where someone had done a fantastic job with the E-620/14-42mm f2.8.

Is it simply that the 14-42mm 3.5-5.6 isn't an ideal lens for this? Either that or should have composed the image with a subject in the frame to increase AF lock (ie. tree line) ?
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Old Nov 13, 2012, 9:25 AM   #2
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When I had the 14-42mm I noticed it is very hard to achieve focus in low light situations, it is a very sharp lens but for this kind of photography I think is not a good choice.

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Old Nov 13, 2012, 9:45 AM   #3
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Don't you have the ability to turn AF off and use manual focus?
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Old Nov 13, 2012, 9:57 AM   #4
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Don't you have the ability to turn AF off and use manual focus?
I think so. However, the viewfinder or LCD doesn't provide an adequate view to determine if the focus in good or not.

I think I just need to get a better lens. Which was my initial thought on this whole thing.
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Old Nov 13, 2012, 9:59 AM   #5
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If you're focusing on the stars you're at hyperfocal distance - you really don't need viewfinder confirmation.
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Old Nov 13, 2012, 10:36 AM   #6
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Quote:
Originally Posted by TekiusFanatikus View Post
I think so. However, the viewfinder or LCD doesn't provide an adequate view to determine if the focus in good or not.

I think I just need to get a better lens. Which was my initial thought on this whole thing.
Hi,

Before you give up on this lens, you might try setting up your camera on a tripod again, use the same settings. But, this time instead of stopping at ISO 400, go up to as high an ISO as the E620 will allow. This should allow you enough light to "see" the image on your viewfinder. I would then set for manual focus and use the lcd screen to focus the lens. Once that's done, leave it in manual focus and reset you ISO back down to ISO 400, take your photograph.

should work.
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Old Nov 13, 2012, 11:30 AM   #7
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Quote:
Originally Posted by zig-123 View Post
Hi,

Before you give up on this lens, you might try setting up your camera on a tripod again, use the same settings. But, this time instead of stopping at ISO 400, go up to as high an ISO as the E620 will allow. This should allow you enough light to "see" the image on your viewfinder. I would then set for manual focus and use the lcd screen to focus the lens. Once that's done, leave it in manual focus and reset you ISO back down to ISO 400, take your photograph.

should work.
Zig
Interesting approach. I'll give this a shot ASAP. Thanks!
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Old Nov 14, 2012, 9:46 AM   #8
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Quote:
Originally Posted by TekiusFanatikus View Post
I think so. However, the viewfinder or LCD doesn't provide an adequate view to determine if the focus in good or not.

I think I just need to get a better lens. Which was my initial thought on this whole thing.
I think John means set the focus to infinity. If the stars aren't at infinity nothing is.
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Old Nov 14, 2012, 10:23 AM   #9
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Thanks Ted - that's what I meant
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Old Nov 14, 2012, 3:48 PM   #10
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G'day Dan

Ah mate - I've had this dilemma many times with the photo workshops I run
Doesn't matter whether it's an Oly or Canon or Nikon or Pentax ... NONE will autofocus on the stars at night

So as the other fellas above have suggested -
immediately go to MF operations
I suggest iso-1600
Take 1x image at 20secs > look closely for focus accuracy
If changing focus, turn lens focus ring 1mm only and try again ... you might need 3 or 4 focus attempts to get it 100%. If you're worried that the focus might change during later exposures, use some masking tape on the focus ring to stop it moving

Q- what sort of exposure time do you have in mind?

If you [or any others here] would like to receive a 4-page PDF on shooting the stars, PM me to arrange it
Regards, Phil
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