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05-25-2011, 05:25 PM   #1
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Manual focusing ease with different lenses

When comparing e.g. the DA 35 mm macro to other lenses, the focus from about 1 m (3 ft) to infinity looks very compressed on the focus scale (i.e. the focus ring would have to be turned very little to change the focus from 1 m to infinity). Does that make the lens harder to manual-focus compared to other lenses?

The same question goes for today's non-macro lenses compared to older lenses. Compared to my old M 50 1.7, all modern lenses seem to have rather compressed focus scales from a few meters (10 ft) to infinity. Compared to the FA 31 1.8 Limited, the 1.7 is turned about five times as far to go from 1 m (3 ft) (judging from pictures of the 31).

Is manual focusing harder to do precisely on newer lenses?

I will use a KatzEye focusing screen very soon (waiting for it to arrive), so that should not be the limiting factor (which I would say is the case with the stock screen - today I have to guess or use live-view).

Those of you who use newer lenses with less throw on the far end of the focusing scale: do you think that manual focusing them works just fine, or can it be "to sensitive"?

05-25-2011, 05:30 PM   #2
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My experience is that the wider the lens the harder to focus due to the depth of field apparent in the view finder. Add to this the tendency for AF lenses to have short manual focus throw and precision is lost as well
05-25-2011, 05:53 PM   #3
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Hi hjb981,

I am on the same boat! Manually focusing DA*200/2.8 is difficult as the focusing ring turn rather "quick", whereas the focusing throw on M200/4 is smooth & easy. 90% of my lenses are MF and can be use on my Kr, K5 & K7, but I find my focusing ability is way off from using the same lens on a film camera such as MX. Same apply to the AF lenses when I use MF on them. I shoot existing light a lot and this problem has really stumped me. Hopefully you can tell us whether a KatzEye helps in manual focusing.
05-25-2011, 06:11 PM   #4
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I have split image focusing screens in both my K10D and *istD and it does help a lot

05-25-2011, 07:20 PM   #5
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QuoteOriginally posted by hjb981 Quote
Is manual focusing harder to do precisely on newer lenses?
Usually, but not always. Some modern lenses still have enough focus throw to focus manually. And manual focus lenses are still being made - not all new lenses are AF.

The compression is one of the blessings of autofocus. You can't have fast AF and a long focusing throw.
05-25-2011, 08:10 PM   #6
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QuoteOriginally posted by Laurentiu Cristofor Quote
The compression is one of the blessings of autofocus. You can't have fast AF and a long focusing throw.
Quite right! AF and especially DA lenses have short throws, just to speed up the AF. I typically *don't* try to MF any of my few AF lenses. If I want the speed of AF, that's what I use. If I want the precision of MF, I use some of my many MF lenses. Different tools for different purposes, eh? And I use CIF (catch-in-focus) extensively with my MF lenses, basically a manual extension of the focusing system but with finer control.
05-25-2011, 08:58 PM   #7
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QuoteOriginally posted by Lowell Goudge Quote
My experience is that the wider the lens the harder to focus due to the depth of field apparent in the view finder.
you also get a similar effect with using lenses faster than f/2.8 with the standard focusing screen which can make focusing a 50mm f/1.2 a real challenge.
05-25-2011, 09:26 PM   #8
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For me it works the other way round!

A fast lens like the 1.2 has a very shallow DOF wide open so it is easier to see when it it in focus. In other words it is easier to get an in focus shot with say a 50/1.2 "shot at F5.6 than an F4 Macro shot at 5.6.

Kim

QuoteOriginally posted by Digitalis Quote
you also get a similar effect with using lenses faster than f/2.8 with the standard focusing screen which can make focusing a 50mm f/1.2 a real challenge.


05-25-2011, 10:29 PM   #9
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QuoteOriginally posted by Kim C Quote
For me it works the other way round!

A fast lens like the 1.2 has a very shallow DOF wide open so it is easier to see when it it in focus. In other words it is easier to get an in focus shot with say a 50/1.2 "shot at F5.6 than an F4 Macro shot at 5.6.

Kim
I'm wondering if what Digitalis had in mind was working with a fast lens set to a wide aperture - in other words, with a shallower DOF, which would make focusing errors more apparent in the final image. This would be exacerbated by the fact that the modern focusing screens don't "see" the extra light from a fast lens, and so the shallower DOF isn't actually seen in the viewfinder, only the final image.

This is one reason for going to a replacement focusing screen (the other being the presence of a split-prism focusing aid). I must say, I would fit the replacement screen I bought in a heartbeat, but for the fact that I'm worried that a) I might mess something up and b) I'll need to re-shim (which sounds like a really tedious task).
05-26-2011, 02:07 PM   #10
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MJL: I will try to remember and report back when I get my KatzEye focusing screen. It will probably be another couple of weeks though, since they need to get the paypal transfer through, make the screen and ship it to me.

DA 35 F/2.8 macro:
I was reading about the DA 35 F/2.8 macro, and in the review I found, they say that it is easy to focus manually because of the extensive throw - about 300 degrees (almost a full turn). However, all that throw is below 0.5 m (2 ft). That makes me think that it is easy to manual focus for macro photography, but hard to manual focus for "normal" photography (non-macro). Is there anyone who has this lens and would be willing to comment on this?
05-26-2011, 02:58 PM   #11
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QuoteOriginally posted by hjb981 Quote
DA 35 F/2.8 macro:
I was reading about the DA 35 F/2.8 macro, and in the review I found, they say that it is easy to focus manually because of the extensive throw - about 300 degrees (almost a full turn). However, all that throw is below 0.5 m (2 ft). That makes me think that it is easy to manual focus for macro photography, but hard to manual focus for "normal" photography (non-macro). Is there anyone who has this lens and would be willing to comment on this?
This is pretty much on the money. At short distances the 35Ltd is very easy to focus precisely -- less so further out. Though, in my experience with the lens I found that I was stopping down for most shots past a few feet out because it doesn't perform all that well at wide apertures at a distance from your subject; when you're stopped down your DOF is wider and precision in your focusing is somewhat less critical.
05-26-2011, 03:29 PM   #12
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QuoteOriginally posted by v5planet Quote
This is pretty much on the money. At short distances the 35Ltd is very easy to focus precisely -- less so further out. Though, in my experience with the lens I found that I was stopping down for most shots past a few feet out because it doesn't perform all that well at wide apertures at a distance from your subject; when you're stopped down your DOF is wider and precision in your focusing is somewhat less critical.
Is this a consequence of it being a macro lens? In other words: would a similar lens that is not made for macro work have better image quality at larger distances? I am not asking about the focusing now, but rather if there is a difference in image quality if both lenses are focused properly at a far away subject.
05-26-2011, 03:40 PM   #13
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QuoteOriginally posted by hjb981 Quote
Is this a consequence of it being a macro lens? In other words: would a similar lens that is not made for macro work have better image quality at larger distances? I am not asking about the focusing now, but rather if there is a difference in image quality if both lenses are focused properly at a far away subject.
I can't and won't make any blanket statements on this, because I don't know the answer. It would make sense for macro lenses to perform strongest at ranges near their minimum focus distances, as they are designed and marketed for this precise purpose; having said that, I don't know if macro lenses typically show weakness at longer ranges or even if my experience with my 35Ltd is the norm.
05-26-2011, 04:12 PM   #14
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I don't know about the 35 Macro. However, in general terms a "normal" lens is optimised for the light waves entering the lens almost parallel and being "bent" sharpely in.

Once you get near lifesize, the situation is quite different with a similar angle on both sides. Once you go larger than 1:1 you should reverse the lens. If not you make the situation worse. Larger than 1:1 with the lens reversed buts the "angles" on the right side again as the object tends to be nearer the lens than the film plane.

Macro lenses do tend to be optimised for close work. ie with the light angled on both sides and it is much less important to reverse a true macro lens. However, optically, this shouldn't make much difference to the ease of focus, it would be more likely to affect such things as CA.

Mechanically, it could be different. Most macro (or at least MF) ones tend to have a long focus throw because the DOF at very close ranges is so small. ( The Voigtlander 125mm has about 1 3/4 full turns from end to end) At longer ranges the DOF is much greater. With a short throw lens the focus does seem to "snap" in and out more than with a macro which could make it easier to judge when the lens is properly focussed.

Kim

QuoteOriginally posted by hjb981 Quote
Is this a consequence of it being a macro lens? In other words: would a similar lens that is not made for macro work have better image quality at larger distances? I am not asking about the focusing now, but rather if there is a difference in image quality if both lenses are focused properly at a far away subject.
05-27-2011, 05:53 AM   #15
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Thank you for your informative and balanced answers. When I get my split prism focusing screen, I think that I will try to find opportunities to try for myself with some different lenses. One thing that I am curious about is how the focus works on the DA 35 F/2.4. It does not have a focus scale (I am not thrilled about that), and I wonder if it can be infinity-focused by just turning in that direction until it won't change the focus anymore. This is the case with my manual lenses. It is, however, not the case with the DA 18 - 135 F/3.5-5.6. With that lens, it is possible to focus beyond infinity (i.e. so that nothing is in focus at any distance). Another peculiarity with that lens is that it changes focus distance when zoomed, so that it has to be refocused after zooming (this design is perhaps the reason it does not have a focus scale). I would like to be able to set infinity focus just by turning to a stop - this helps a lot when photographing things that are far away in the night time (when there is too little light for the auto-focus to work). Does anyone know how the DA 35 F/2.4 works in this regard?

/Jonas
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