Manual Focus with Older Lenses

I've searched around, but I can't seem to find any threads on this.

Like several others on this forum, I want to use some Leica-fit lenses (both screw and bayonet) on my GF1, so I'm about to order an adapter. Obviously, for accurate focusing I'll need to focus at full aperture, but I'll then have to stop down to the working aperture, which seems a very inefficient way to work. Either that, or always shoot at full aperture, which is equally unsatisfactory. What are the rest of you doing?

And while I'm here - for these manual-focus lenses, is the EVF a useful accessory? So far, I've resisted buying one.

David

I use the brute force method of focusing.

I first change the focus until I see the image go in-focus and then just slightly past. Next I hold the shutter down (set to multiple) and at the same time rotate the lens/focus in the oposite direction...while blasting off 5 or 6 shots. This way I am guaranteed to get one image in almost perfect focus. You can do it extremely quickly too so you don't miss any shots. The draw back is you have a lot of not quite in focus shots you need to delete.

You can focus with the lens stopped down because the camera boosts the light, plus you can go to magnified view to make focusing more precise.
--
The wood is clear between the knots.

Everdog's brute force approach is quite interesting. I do the same with regard to steadiness and slow shutter, but never contemplated FPS exposures for focus. (Always enjoy experiences of others, how resourcefulness is applied to limitations).

And now that I have the Panasonic EVF (on the LX5), I understand why. Using the Olympus EVF, with legacy lenses it's not so much that I can determine where the focus sits, but rather when the image turns from soft and saturated to harsh with little saturation, I know focus is attained (thinking of sunny broad scenes, particularly, and quick studies - slower studies of less contrast scenes are easier). And this is on a much better EVF. Panasonic's current detachable EVF I can only appreciate for compositional and exposure considerations - focus I have to rely on the LX5 to attain.

I hear the GF1's LCD is great (IIRC), so that might be the preferred MF approach - but I rarely turn to LCD composing unless on a tripod, so my experience isn't great at all in that dept.

For whatever that's worth. . .

--
...Bob, NYC

'Well, sometimes the magic works. . . Sometimes, it doesn't.' - Little Big Man

http://www.bobtullis.com

I had my doubts about accurate focusing at smaller apertures, even with the extra brightness and the magnified view, but if this works for you, then I'll give it a try.

thanks,
David

Ron Evers said:

You can focus with the lens stopped down because the camera boosts the light, plus you can go to magnified view to make focusing more precise.
--
The wood is clear between the knots.

Click to expand...

Bob Tullis said:

I hear the GF1's LCD is great (IIRC), so that might be the preferred MF approach

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It's very good, better than I expected. It works well enough for MF but I find all LCDs awkward for anything but tripod use (or with AF). The optional EVF is very expensive and has awfully low resolution for use with MF - too low for me - so I intend to use the LCD with a Clearviewer for MF.

The Crearviewer is much cheaper and far better functionally than the optional EVF; can't be bad

--
John Bean [GMT]

Even with 14x magnification on the much better Oly EVF, I am unable to focus as accurately at smaller apertures as I can wide open. Everdog's approach is something I'll have to try, although I'm not convinced that it is more convenient than focusing wide open and then stopping down. The hassle of deleting OOF shots will be worth it if I get more keepers.

DavidinDenmark said:

I had my doubts about accurate focusing at smaller apertures, even with the extra brightness and the magnified view, but if this works for you, then I'll give it a try.

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Actually, focusing at full aperture has potential problems with faster lenses. Due to spherical aberrations, the focus on many fast lenses will shift. The fact that you are also stopping down usually covers this, but not necessarily completely and the mid-point of your DoF may be different than what you want. BTW, this is one of the reasons that some DSLRs now allow users to fine tune the focus on their cameras with manual tweaks. The AF sensors used in DSLRs typically look through the lens exit pupil at f/2.8 f/4 and f/5.6 equivalent apertures. But if your taking aperture is different, and you have a fast lens, these focus measurements aren't necessarily going to give you the best focus.

http://toothwalker.org/optics/spherical.html

(Read the whole article - or go to the section on Focus Shift. Actually, I suggest reading the entire site.)

So actually, I think focusing stopped down is very sensible and preferred. You focus through the aperture that you will take the picture with. What you see is what you will get. And if you stop down so far that the focus point is hard to find precisely because DoF is so great, then focus accuracy probably isn't critical anyway.

When shooting at large and moderate apertures, I rack the focus back and forth and fine the middle spot between the to points where the focus is obviously out of focus. Of course there is always the magnified view. And another trick when using the eye level viewfinder of the GH1 is that I look for aliasing - either "stairstep" aliasing from contrasty edges, or moire from fine repeating patterns. When you can see the "stairstep" aliasing, you are very close to exact focus. It is very hard to notice the eyelevel finder display pixels when the subject is out of focus.

--
Jay Turberville
http://www.jayandwanda.com

Jay Turberville said:

And if you stop down so far that the focus point is hard to find precisely because DoF is so great, then focus accuracy probably isn't critical anyway.

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An obvious point often overlooked. Comes naturally to anyone who was used to focusing slow, wide lenses on a matte focus screen back in the day; now we have a new generation learning it all for the first time.

--
John Bean [GMT]

I know that the practice seems nearly medieval when cameras had aperture lock while Kennedy was running for office. IMO awkwardness is the price of having the option to use any lens up to and maybe including whatever the CIA puts on their satellites.

I thought I invented that. Sometimes I do that when I don't have time to screw around, but mostly I use the old fashioned approach described below.

Tim F 101 said:

I know that the practice seems nearly medieval when cameras had aperture lock while Kennedy was running for office. IMO awkwardness is the price of having the option to use any lens up to and maybe including whatever the CIA puts on their satellites.

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Well, I just found out that my FD-adapter has an aperture lock! Aperture can be switched to full-open and back with a tiny twist! It seems that this only works with 'FD-new' lenses, though...

pannumon said:

Well, I just found out that my FD-adapter has an aperture lock! Aperture can be switched to full-open and back with a tiny twist! It seems that this only works with 'FD-new' lenses, though...

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Nope, that should work with breech lock FDs and even FLs as well. Fls btw have A/M switch that has the same functionality on m4/3 body.

Lucky stiff. My cheapo Nikon adapter certainly does not. It also goes a bit past infinity and grabs lenses awfully tight. Maybe I should have ponied up for a real one...

I have the Voigtlander Nokton M mount F1.5 and have no problems focusing at any aperture

In practice we buy these legacy lenses mainly for their brightness so would shoot wide open most of the time, at least that's what I do
manual focusing can be cumbersome if you're used to superfast AF speed

needless to say when your subject is fast moving manual focus could be hit or miss
give it a try but do expect OOF results
cheers ;-))

fermy said:

pannumon said:

Well, I just found out that my FD-adapter has an aperture lock! Aperture can be switched to full-open and back with a tiny twist! It seems that this only works with 'FD-new' lenses, though...

Click to expand...

Nope, that should work with breech lock FDs and even FLs as well. Fls btw have A/M switch that has the same functionality on m4/3 body.

Click to expand...

Thanks! I tried some more and you are absolutely right! Without your advice I would not have realized this. That's what you get when you don't do your homework and learn how the pins function... Need to try some FL lenses also.

Tim F 101 said:

Lucky stiff. My cheapo Nikon adapter certainly does not. It also goes a bit past infinity and grabs lenses awfully tight. Maybe I should have ponied up for a real one...

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I think they all focus past infinity, even the "official" ones. No idea why; I've read various hypotheses but none of them were very convincing.

I spend a bit of time shimming a new adaptor to give exact infinity focus, the three I've done so far needed significant shimming of about 0.3mm.

I find focus scales on lenses useful sometimes and it seems a shame to leave them without purpose

--
John Bean [GMT]

I took this today with a Vivitar 70-150/3.8 & focused with it @ f11. ISO 400 & 1/125s. Not sure where the zoom was.



--
The wood is clear between the knots.

Normally if there is enough light to step the lens down I just step it down to what I want and focus with that setting... It is not that hard to do as you get "real preview" with the lens stepped down...

One of the reasons why AF systems needs the lens wide open is both that they are very "bad sighted" they need loads of light to see anything, but also to be more accurate... With a high aperture focus is "fine" in a wide field and so the camera is not able to find the "perfect" spot... When you focus you can view the entire image and say "I want focus sharp here, check, I want focus unsharp here... Have to move lens a bit forward... check, is focus still sharp at point I want sharp? check, take picture..." This the camera can't (yet?) do

DavidinDenmark said:

... Obviously, for accurate focusing I'll need to focus at full aperture, but I'll then have to stop down to the working aperture, which seems a very inefficient way to work. Either that, or always shoot at full aperture, which is equally unsatisfactory.

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I focus at f2.8 or wider, then stop-down if needed.
That's life.
Blooming easy with the G1's EVF.