Should I consider focus throw when buying manual focus SLR lenses?

[NowhereMan]

I bought a Nikon FE2 a while ago. Since I started buildung a small collection of Nikon manual focus lenses I've been noticing that some lenses need much more rotation to cover the entire focus range than others. Generally speaking the older AI models have much longer focus throws than the newer AI-s models. For example, the 50mm f/1.8 AI has 210° whereas the AI-s has 130°.

Given that I sometimes found it difficult to focus precisely I reasoned that a long focus throw would help in that regard. After all, the distance between, say, the 2m and the infinity marks on the lens is sometimes tiny. However, when I tested the two above mentioned 50mm lenses against each other, I didn't get the impression that I was able to focus more precisely with the longer focus throw. What I found is that the longer focus throw was most noticeable in the close focus range (below 1 meter), which isn't the range that I had most trouble in.

Now I am wondering what other, more experienced manual focus photographers think about this issue. Do you think focus throw is something to pay attention to when buying lenses, or not at all? Do you think it's easier to focus with a longer focus throw? Or do you prefer the quicker action of the shorter focus throw?

At last, I am also wondering why Nikon chose to dramatically shorten the focus throw on their MF lenses when moving from the AI to the AI-s models. Do you think it was simply a matter of preference among their customers?

 

[ic-racer]

I have been collecting some of those long focus throw pre-AI lenses for my F and F2. They are harder to use, but have excellent build quality, good optics, easy to repair. They are usually inexpensive because they don't work on digital cameras.

This is what I have picked up so far and they are all fantastic. These are all "Pre-AI" design and construction but I did put AI aperture rings on some of them.

80-200/f4
35/f2.8
50/f1.4
28/f3.5
24/f2.8
55/f3.5 Micro

 

[NowhereMan]

You mean they are harder to use than lenses with a shorter focus throw?

 

[ic-racer]

You mean they are harder to use than lenses with a shorter focus throw?

I think so, but that is personal preference. For example I have five different 28mm F mount, including AF-D that can manual focus. For me, the ones with the short focus throw (like the 28/2.0 AI-s and 28/AF-D) snap into focus easier than the old Pre-AI 28/3.5

 

[BrianShaw]

I would agree. The shorter focus throw was an improvement in usability.

 

[brian steinberger]

I prefer a shorter throw.

 

[Nitroplait]

It depends on the way you prefer to take photos.
If you spend time contemplating composition and where to place the plane of focus, then a long focus throw shouldn't matter.
If you are more into capturing a moment, then the shorter throw is probably preferable.

I find that the incredibly low price of many great non-AI lenses often makes the decision easy.

 

[Bob Merlin]

A longer throw can make critical focusing easier.

 

[Nitroplait]

A longer throw can make critical focusing easier.

Except OP doesn't feel that way for his shooting style.

 

[NowhereMan]

I find that the incredibly low price of many great non-AI lenses often makes the decision easy.

In my case I can't use non-ai lenses with the FE2. The AI / AI-s lenses aren't dirt cheap but mostly inexpensive too (except a few "classics" which are popular with digital photographers).

 

[pentaxuser]

You appear to have answered your own question in what you have told us of your experience and most here seems to be support your experience - assuming others' experience really matters compared to your own

My thought is that even if they all disagreed with your experience, it doesn't matter. In such matters only your experience counts as it is you who is turning the lens

pentaxuser

 

[loccdor]

What I wish from using the Canon nFD super telephotos (300mm-1000mm range with teleconverter) is that they had more focus throw near infinity. It's quite hard to accurately focus them there, going out of focus is just a slight twitch of the finger, and finding exact focus is difficult. For example when taking a picture of the moon I might need 5 or 10 tries to get a really snappy shot.

It's funny because I read the literature they released these lenses with and it said they'd developed a system to increase focus throw near infinity. Can't imagine how bad it was before they did that.

I also have a Sonnar 180mm for Pentacon Six and the long focus throw doesn't really help much with focusing, it mostly makes it more laborious to turn the old, dirty helicoid on the heavy lens. So I guess there's a sweet spot and it's all about balance.

In a perfect world, the looseness or tightness of the focus would be adjustable via a control. And you wouldn't want a linear adjustment - you'd want more throw toward infinity and less when closer.

 

[NowhereMan]

You appear to have answered your own question in what you have told us of your experience and most here seems to be support your experience - assuming others' experience really matters compared to your own

My thought is that even if they all disagreed with your experience, it doesn't matter. In such matters only your experience counts as it is you who is turning the lens

Let's put it like this: If a majority of people here contradicted my own experience I would definitely do some more testing and comparing. But if a majority confirms my experience I feel reassured.

 

[NowhereMan]

In a perfect world, the looseness or tightness of the focus would be adjustable via a control. And you wouldn't want a linear adjustment - you'd want more throw toward infinity and less when closer.

Exactly. That's what I was hoping for when I bought the 50mm f/1.8 AI: more throw toward infinity. Because it's the range between around 5 meters and infinity where I find focusing most difficult. But as I said, the longer focus throw is mostly noticeable in the short range where I don't need it.

 

[wiltw]

Consider that at close distances, it is easier to visualize any focus error inherently because lesser DOF readily reveals focus error, while at long distances the greater DOF masks focus error.
With a purely linear focus relationship, 10 degrees of rotation of the focus ring might represent +-30' of focus range at distance, while the same 10 degrees of rotation might be +-2' of focus range up close, and (assuming 135mm lens) DOF up close is 200cm while out far (e.g. 100m) DOF is 118m (wide open focusing at f/2.8), making focus error inherently difficult to even see without a really big swing of distance.

 

[MattKing]

Let's put it like this: If a majority of people here contradicted my own experience I would definitely do some more testing and comparing. But if a majority confirms my experience I feel reassured.

Before I approached your question this way, I would find out first how people used the lenses in question, and then limited my considerations to those whose usage patterns were at least similar to my own intended use.
When I did a fair amount of event photography, or when I do anything like street photography, short throw is really useful.
When the camera is being used for landscapes or other subjects that give me lots of time to work, it rarely matters.
Also, if you take lots of photos where the depth of field is shallow, and there are many potential planes of focus, where only one is desired, you may need to maximize the differentiation of those different planes, which may lead you to prefer a long focus throw.

 

[Sirius Glass]

When one focuses a lens with a long focus range, focu the lens quickly.

 

[Paul Howell]

With wide to shot telephotos I have found that the focus throw does not makes much of a difference. Once to a 200mm and longer it does make a difference. In practice, a lens like a Minolta 300 MD has a very long throw, very long, but in most cases I am focusing at given range the throw is manageable. Say I'm shooting wildlife between 70 and 200 feet, the throw is only a few degrees, but at near distance day 25 to 40 feet the throw is very long. It's for that reason when shooting wildlife I use lens with internal focus and in most cases an AF lens.

 

[abruzzi]

In a perfect world, the looseness or tightness of the focus would be adjustable via a control. And you wouldn't want a linear adjustment - you'd want more throw toward infinity and less when closer.

Except the opposite of that is specifically why macro lenses (Micro-Nikkor in Nikon parlance) have especially long focus throws--close up a small amount of turn on the focus can have a huge impact on what is actually in focus.

To the general qusetion, I prefer a longer throw, and almost all of my Nikkor lenses are pre-AI and have a pretty appropriate amount of turn. The only AI/AIS lenses I have a Nikon E lenses on an FA.

 

[NowhereMan]

When I did a fair amount of event photography, or when I do anything like street photography, short throw is really useful.
When the camera is being used for landscapes or other subjects that give me lots of time to work, it rarely matters.

Well, if I was an event or sports photographer back in the early 80ies I'd certainly want a shorter throw. Today I'd never use a MF camera for fast action. I am almost exclusively using the FE2 in situations where I have ample time to focus.

 

[DREW WILEY]

It's more the "feel" of it which matters to me. I tend to prefer classic older lenses with longer throw, and often better mechanical build too.

 

[250swb]

If you know your lens and use it enough I don't think focus throw makes any difference unless it's a tele lens and you want a more subtle ramp up to 'focused', in which case a long throw is best, but isn't that what lens designers try for anyway? I find it hard to understand why anybody thinks the designer hadn't thought about this and why you think it's a random characteristic and not an intentional choice?

 

[reddesert]

Consider that at close distances, it is easier to visualize any focus error inherently because lesser DOF readily reveals focus error, while at long distances the greater DOF masks focus error.
With a purely linear focus relationship, 10 degrees of rotation of the focus ring might represent +-30' of focus range at distance, while the same 10 degrees of rotation might be +-2' of focus range up close, and (assuming 135mm lens) DOF up close is 200cm while out far (e.g. 100m) DOF is 118m (wide open focusing at f/2.8), making focus error inherently difficult to even see without a really big swing of distance.

For a unit focusing lens (without internal focus or CRC = close range correction), the helical pitch fixes how much the lens moves forward/back for N degrees of focus ring turn. The forward/back movement can be compared to the depth of focus in the image (film) space. And the depth of focus in the image space, is constant for both near and far subject distances. So at the same f-number, the DOF is covered by the same focus throw, whether near or far.

This is why the same set of depth-of-field scale marks works for both far-away and close-up subjects. If 10 degrees of focus turn corresponds to f/11 on the DOF scale, that holds both near and far. However, in subject-space terms, of course the DOF is much smaller physical distance for close-up subjects, as you say.

Anyway, my guess is that for the OP, focus throw isn't a significant cure for their issues, and other things to try are:
- practice more, it gets easier
- check to make sure you don't need a diopter
- practice using the matte ground glass surface to focus. This is easier to see with fast lenses, while the split-image is not more precise with an f/1.8 lens versus f/2.8, for example.
- check the DOF scale, maybe the amount of focus precision you are concerned about is covered by the DOF anyway.

 

[RalphLambrecht]

This why I no longer buy MF lenses;AF is faster and more accurate!