[Squier]

I seem to have to correct a lot of my photos in PP for OOF, especially Tele shots.
I normally use a tripod for long teles and remote cable release

I have different make lenses, so this should eliminate brand problems.

I have read here and been told that the focus screen on the K10 is cr*p, but how would this affect focus at infinity ?

For example, a moon shot requires the focus ring to be turned as far as it will go, and if this results in blurred photos while using a tripod and remote cable, i cant see this being the fault of the screen, if the lens focus ring is right at its limit , right at the end of its travel. This means to me, that changing the screen isnt going to change the travel of the focus ring. If its at full travel, then it can only be turned back, and therefore wont be at infinity anyway.

Is it possible that its the sensor , or is it most of my lenses are bad ?

I have ordered a new screen anyway, because i really dont like the native K10 screen, but surely this will only help focusing issues that are not at infinity ?

I dont mind being corrected if i've got this all wrong

[Marc Sabatella]

Some lenses actually turn past infinity. You can't assume that turning the focus ring until it stops will put the moon in focus - you have to actually look at the image (or trust the AF system). The new screen might make it easier to check this, but it should be possible with the stock screen - you just have to take practice and not assume that if it looks sort of in focus, it probably is.

Note the moon moves, and pretty fast too. So unless you're shooting a pretty high shutter speed, you'll get motion blur. Also, ar using the timer for mirror lockup?

[Squier]

Hi Marc - just using a remote cable , no mirror lock up. I can't be making the camera wobble with a remote, surely ?

I did look at the image when focusing to infinity, and backing the focus ring off a tiny amount burred the image, but then we're back to trusting the screen to be telling the truth

I have taken your previous advice about screens, as just mentioned above, and ordered a split image with microprism + grid, from Focusing.com. I didnt like the look of the Virtual or Jinfinance types.

PS 1/125 @ F8 ISO 100, was the best i could get

[Wheatfield]

Hi Marc - just using a remote cable , no mirror lock up. I can't be making the camera wobble with a remote, surely ?

Surely you can.
Depending on the tripod, the camera can bounce around quite a bit all on it's own. If the camera is on a tripod mounted lens, that just makes things worse.

[Marc Sabatella]

Hi Marc - just using a remote cable , no mirror lock up. I can't be making the camera wobble with a remote, surely ?

*You* can't, but the mirror will shake the camera all by itself. That's why they give you a lockup option. Shots on tripod should always be taken that way when possible, with any SLR.

I did look at the image when focusing to infinity, and backing the focus ring off a tiny amount burred the image, but then we're back to trusting the screen to be telling the truth

It should be if aligned properly. The time it lies is when shooting scenes with very wide apertures (f/2.8 or larger) where the DOF is actually shallower than what the focus screen is capable of showing. I don't think that's happening here.

PS 1/125 @ F8 ISO 100, was the best i could get

Depending on what focal length you're at, that should be just barely fast enough to avoid noticeable motion blur. Although if you're shooting over 500mm (just a guess!), that might not be fast enough.

Moon photography is tricky in lots of ways - most people overexpose it pretty severely and thus lose detail due to clipping.

[mikeSF]

Some lenses actually turn past infinity.

reminds me of the Spinal Tap line, "These [amps] go to eleven."

[Squier]

Surely you can.
Depending on the tripod, the camera can bounce around quite a bit all on it's own. If the camera is on a tripod mounted lens, that just makes things worse.

Yup, it was lens that was mounted. There's 3 choices when mounting this 350mm Tele - there's 2 on the lens body itself, and of course the camera. I chose the mount furthest away from the camera body, thinking i was helping reduce wobble.

*You* can't, but the mirror will shake the camera all by itself. That's why they give you a lockup option. Shots on tripod should always be taken that way when possible, with any SLR.

It should be if aligned properly. The time it lies is when shooting scenes with very wide apertures (f/2.8 or larger) where the DOF is actually shallower than what the focus screen is capable of showing. I don't think that's happening here.

Depending on what focal length you're at, that should be just barely fast enough to avoid noticeable motion blur. Although if you're shooting over 500mm (just a guess!), that might not be fast enough.

Moon photography is tricky in lots of ways - most people overexpose it pretty severely and thus lose detail due to clipping.

I'll try the lock up option next. Perhaps i have never noticed problems at the wide end, because i rarely shoot wide on any lens i have.

I use the Tamron Flat Field BBAR MC 2x TC with the 350mm Tamron constant f4.5. ( 700mm ) The arrangement of the TC with its built in aperture ring, sets the aperture down 2 stops to f8 maximum.
I also bracket to allow for over exposure, and shoot DNG

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Last edited by Squier; 05-07-2009 at 03:27 AM.

[Marc Sabatella]

I use the Tamron Flat Field BBAR MC 2x TC with the 350mm Tamron constant f4.5. ( 700mm ) The arrangement of the TC with its built in aperture ring, sets the aperture down 2 stops to f8 maximum.

That seems like a long enough focal length that you might indeed be seeing motion blur at that shutter speed. If you don't want to open up the aperture a little (I'm assuming stopping down that far is pretty much necessary to get decent sharpness), then you might need to increase ISO. I guess it's also worth questioning if that lens & TC combo is even capable of the sort of sharpness you might want. But I'm guessing maybe you've used it successfully for other inds of shots?

Also, that sounds like a *very* heavy combo. In addition to mirror lockup, you had better have an *extremely* sturdy tripod.

Some pictures would be interesting. both to help diagnose what you are seeing, but also, because I'm curiously what the moon might look like through such a rig!

[Squier]

With the BBAR MC 2x TC, it stops the Ap down 2 stops as soon as i mount the lens and
TC onto the camera.

I thought this was normal if you were adding a 2x TC - having add 2 stops ? In my case,
the Tamron TC does this for me, as it has an aperture ring on the TC. I cant focus wider than F8.
The only way to do that would be to use a regular 2x TC....which i could try, as i have one, but
what about the 2 stop rule when using a 2x TC ?

I will try the option of ISO increase. I've only shot @ 100, so this could be upped a tad

Theres no telling if the combo of Tamrom 350mm / constant f4.5 + Tamron TC 2x is a good one,
as i have nothing bigger or better to compare it with. My next longest lens is a 200mm

Anyways - here's a shot @ 700mm / f8

Oh yeah the tripod is a Manfrotto Pro Art 144

[Squier]

Just looking for a bad moon shot - back in a mo Marc

[Squier]

[Wheatfield]

Yup, it was lens that was mounted. There's 3 choices when mounting this 350mm Tele - there's 2 on the lens body itself, and of course the camera. I chose the mount furthest away from the camera body, thinking i was helping reduce wobble.

Lens mounts are a compromise. They reduce strain on the camera body (a heavy lens can warp the chassis or even pull the mount right off the camera), but because the camera and it's vibration are farther from the pivot, there is more leverage for it to show up.
It can take a very heavy or well damped tripod to tame a long lens. I have a 16 pound wood tripod that I have been using under my 600mm lens that seems to do a good job of damping vibraton, but it's a bear to take into the field.
Something a lot of successful long lens shooters do is drape an arm over the lens to damp vibration. It might be something to try.
You can also wrap a bungee cord around the tripod legs at the first lock. Not so tight that you bend things, but enough that the elastic is stretched a bit. This can help quiet the legs if they are singing.

[Squier]

Thanks Wheatfield - anything is worth a try.

next clear night ( not tonight - its overcast ) i'm gonna try the MLU, and then it shouldnt
be long before i receive the new screen - and then i'll be trying again.

Although i've read split screens darken too much at stops like F8, i can change my TC from the
Tamron to the Panagor, and i will then focus at F4.5 ( max for my Tam 350mm ) and then stop down to shoot.

[Marc Sabatella]

With the BBAR MC 2x TC, it stops the Ap down 2 stops as soon as i mount the lens and
TC onto the camera.

I thought this was normal if you were adding a 2x TC - having add 2 stops ?

Yes. I thought you meant you stopped down two stops in addition.

Anyhow, the bird shot looks good at this size. tThe moon shot looks oddly processed - like a combination of too much sharpening and too much NR. And there's kind of a lot of chromatic aberration. That makes it kind of hard to say anything about focus.

[Squier]

Marc - i have edited the above moon shot for another blurry moon, so you can see the blur a bit easier.

You were right about the other shot - i was trying to get rid of blur and other then messing up the shot even further, i didnt manage to