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09-26-2010, 07:30 AM   #1
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Does any longish glass for Pentax have focus limiters?

Hi All,

I have been using the oustanding Sigma 100-300 f4 for shooting soccer lately. I absolutely love this lens, but I am having trouble with some cases where the lens locking focus on the background instead of players on the field. Are there any lenses in Pentax mount usefull for sports that have focus limiters? Does anyone have experience with focus limiters? Thanks.

09-26-2010, 07:44 AM   #2
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the ones that do have focus limiters are rather hard to find and typically expensive. One lens I use for sports and I suggest you keep an eye out for would be the the FA 300mm f/2.8 ED [IF] which shares the trait of being an internally focusing lens like the sigma and it focuses just as quickly (and sometimes quicker, if you're in good light) than the sigma 100-300mm f/4. However, With my own use of the sigma it has the irritating tendency to hunt under overcast/low contrast conditions which the FA300mm f/2.8 doesn't hunt as often.Unfortunately the FA300mm f/2.8 does not have a focus limiter, the only Pentax lenses I know of that have this feature are the macro lenses and I wouldn't recommend them for sports in any case.

Last edited by Digitalis; 09-26-2010 at 07:50 AM.
09-26-2010, 08:29 AM   #3
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The FA*300mm f2.8 of mine had a 3 position focus limiter, unfortunately it was not sharp and pentax would not fix it.
09-26-2010, 08:57 AM   #4
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Digitalis: the FA* 300/2.8 comes standard with a focus limiter. I own one and don't mind posting an image of the lens as proof if needed. The FA* 600/4 and the FA* 250-600/5.6 also have focus limiters, but it's not a slider switch on either of those lenses.

As Tom/Borno indicated, it can be used on 3 different ranges. Unlike his (having focusing issues?), mine is an excellent copy - sorry Tom.

Regards,
Marc

09-26-2010, 09:41 AM   #5
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QuoteOriginally posted by Marc Langille Quote
Digitalis: the FA* 300/2.8 comes standard with a focus limiter. I own one and don't mind posting an image of the lens as proof if needed. The FA* 600/4 and the FA* 250-600/5.6 also have focus limiters, but it's not a slider switch on either of those lenses.

As Tom/Borno indicated, it can be used on 3 different ranges. Unlike his (having focusing issues?), mine is an excellent copy - sorry Tom.

Regards,
Marc
you're right it does, my bad...it has been a very long time since I have used mine FA*300mm f/2.8. I confess I have been making use of my recently acquired Nikkor 400mm f/2.8 ED IF VR on my D3 which is replacing my canon equivalent lens.I use my Pentax K7 with the sigma 100-300mm f/4 alongside this camera and lens setup for those sporting moments where I need the flexibility of a zoom.
09-26-2010, 09:51 AM   #6
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QuoteOriginally posted by Digitalis Quote
you're right it does, my bad...it has been a very long time since I have used mine FA*300mm f/2.8. I confess I have been making use of my recently acquired Nikkor 400mm f/2.8 ED IF VR on my D3 which is replacing my canon equivalent lens.I use my Pentax K7 with the sigma 100-300mm f/4 alongside this camera and lens setup for those sporting moments where I need the flexibility of a zoom.
No worries sir. BTW Digitalis, please consider this a formal introduction/hello! I find your posts thoughtful and informative.

As an FYI, both the FA* 600/4 and FA* 250-600/5.6 have a limiter ring. For reference, is a shot of the focus limited design on the lens (same for both aforementioned):


Best,
Marc
09-26-2010, 11:52 AM   #7
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QuoteOriginally posted by Marc Langille Quote
No worries sir. BTW Digitalis, please consider this a formal introduction/hello! I find your posts thoughtful and informative.

As an FYI, both the FA* 600/4 and FA* 250-600/5.6 have a limiter ring. For reference, is a shot of the focus limited design on the lens (same for both aforementioned):


Best,
Marc
Yes the FA*600 has exactly the some focus limiter; I find it very useful compared to switches cause you can choose the minimum focus distance with maximum flexibility; focus limiter is missing on the DA*300 for instance, and it is a pity cause this lens has a very short focus distance - 1,5 m and when it hunts, it hunts for a while
regards
09-26-2010, 12:28 PM   #8
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I just use pseudo-quickshift and set it to infinity if it comes too close on my Tamron 70-200mm f2.8 and sometimes with the 1.7x tc. It's a little tricky with the AF/MF clutch, and I hold no responsibility for any damages :-p

Note I am referring to pushing the lens release on the body with my right ring(?) finger.

09-26-2010, 05:48 PM   #9
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QuoteOriginally posted by goubejp Quote
BTW Digitalis, please consider this a formal introduction/hello! I find your posts thoughtful and informative.
thank you mate, I do my best to stifle misinformation that gets handed around here like common fact. And my answer to the whole blow up over the FA limited lenses demise(not true, incidentally) was to load up my Pentax MX with T-max and mount the FA31mm f/1.8 and go out and take pictures.

The sigma 100-300mm f/4 does not have quick shift, which is very unfortunate. however having said that due to the fact that the sigma is a autofocusing lens is has a VERY short focus travel considering it's focal length, so focusing manually can be tricky .

i'm hoping the newer sigma 120-300mm f/2.8 APO EX OS DG addresses some of these issues, providing they release it in Pentax mount.

Last edited by Digitalis; 09-26-2010 at 05:59 PM.
09-26-2010, 06:18 PM   #10
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Agreed - taking photos is the best option!!

As you've indicated, I'm interested in the facts, nothing more. I'd rather be immersing myself in photography.

Regards,
Marc
09-27-2010, 10:52 AM   #11
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Thanks everyone for the replies, I apreciate it. Special thanks for the photo of the 250-600 with the focus limiter. I have never seen how they work. So, do you turn that little knob and then rotate that collar to a certain spot? Are there three distinct stops, or is it variable? I see markings for full, 20, 10, does the 20 for example mean only focus 20 meters and closer? It seems like there would be a longer setting than that. In my case, I'm shooting at 30 meters quite often.
09-27-2010, 10:58 AM   #12
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So, for autofocus, of course I have the body set to AF-C, and I guess it's just a question of whether centerpoint or auto works better for the individual user? For me, Auto many times will pick up a player closer that I'm not interested in, but using centerpoint will go to the background too much. Centerpoint has been much better overall. It seems to me what would be most usefull is a "center area" setting where the camera would only search say the middle 10% of the frame, and pick the closer object in that area. It seems that the "point" in centerpoint is a little too small. Am I crazy here? I am using a K10d here, so maybe with a K-x, k-7 or one of the newer bodies with better performing AF-C, this is less of an issue?
09-27-2010, 12:43 PM   #13
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QuoteOriginally posted by jake14mw Quote
Thanks everyone for the replies, I apreciate it. Special thanks for the photo of the 250-600 with the focus limiter. I have never seen how they work. So, do you turn that little knob and then rotate that collar to a certain spot? Are there three distinct stops, or is it variable? I see markings for full, 20, 10, does the 20 for example mean only focus 20 meters and closer? It seems like there would be a longer setting than that. In my case, I'm shooting at 30 meters quite often.
Hi,
it is a mechanical focus limiter; if you turn the limiter to, lets say 20m, it limits the focus from infinity to 20 m; it is mechanical cause when the body finds the "hard stop" caused by the limiter its deduces that it has reached the limit; and tries to focus the other direction. Limiting only the minimum distance is enough for the Safox cause it processes by focusing down and then up when low limit has been reached;
Regards
09-27-2010, 01:16 PM   #14
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QuoteOriginally posted by Eruditass Quote
I just use pseudo-quickshift and set it to infinity if it comes too close on my Tamron 70-200mm f2.8 and sometimes with the 1.7x tc. It's a little tricky with the AF/MF clutch, and I hold no responsibility for any damages :-p

Note I am referring to pushing the lens release on the body with my right ring(?) finger.
Eruditass, can you explain further what you mean? I have the Tamron 70-200/2.8 on my K20D.

I experience the same issue with soccer. I typically use AF-C center point (I can always crop later), but it often finds better contrast in the background (especially as the subjects are moving) and I miss focus. I've got a lot of great pictures of the cars behind the game.

I tried setting my focus point manually and using the lower center point, but this only works when the distance is just right.

Lately I've set up the AF button to "cancel AF" and when my player is in focus (I'm using a split focus screen), I hold the AF button to stop the focus from changing until the action moves significantly. This works well when the player is halfway across the field, or when someone steps into my way for a moment.
09-27-2010, 04:14 PM   #15
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To add or clarify to JP Goube's post: there are no physical stops underneath those markings on the focus limiter, except at "FULL". There is a noticeable click and it stops there (at "FULL").- it's a completely variable setup, using a mechanical limiter.

To further clarify on your comments regarding the distance: the distance scale window also lists 20, 30 and 50 meters. You can set the limiter to this range (50m), which at that point is getting close to Infinity. I rarely go past 7-8 meters with most birding shoots, relying on technique to get closer than normal.

The Power Zoom function on the 250-600/5.6 is very useful and has 3 speeds: slow, medium and fast. It does serve it's purpose with such a long FL lens, although fast moving subjects may not always work! It moves the entire FL in either direction within a second at the highest speed. There is another possibly useful feature: when zooming in either direction, if you choose you can let the camera AF the lens during zooming onto another target without even touching the AF button or shutter button. I don't mean parfocal usage - I mean moving the lens to another target while zooming will cause the AF to lock on the new target automatically. All I have to do is fire the shutter button, since my auto focus is separated to the AF button on the back. Basically I can auto-AF the entire time! Hope I explained it correctly...

However, the PZ it will consume battery life fairly well if used frequently and normally I'll see a few hundred shots less on a K10D w/battery grip if the PZ is used a lot. I carry spares just in case!

Cheers,
Marc

Last edited by Marc Langille; 09-27-2010 at 05:02 PM.
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