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03-29-2007, 07:50 AM   #1
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AF options for 300mm f/4.0?

Hey gang,
I have the SMC300 f/4.0, which is a nice lens, but I continue to have problems consistently focusing at the long end. I use focus confirmation, but I still get too many soft shots. I also have the 1.7x AF converter, and it works mostly (though it's not supposed to), but I'd rather just have an AF lens. Which brings me to my question.

What are my options for autofocus lenses at 300mm and f4.0? AF F2.8 lenses cost too much and are too large, so f4.0 seems like the right spot. I've looked and it seems like my only option is the Sigma 100-300 f/4.0, which gets glowing reviews at FM. I guess I could have a fire sale and get rid of a bunch of lenses and such to fund this purchase, but I want to make sure I'm aware of all the options out there. What does Pentax have coming out that's in that range? Other Sigma or Tamron options? Any advice will be appreciated.

03-29-2007, 08:45 AM   #2
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Just use your eyes. Use the focus indicator as a guide. But at 300mm, I find the magnification pretty good and enough to tell if stuff is in focus.

If you can't determine focus, think of your distance to the subject as having a radius "x". Mentally 'draw' out a bit of the circumference. Or think if drawing a 'curve' with a compass. If you can find something nearby thats a bit more 'edgy' or has distinct details, focus on that, pan back to your subject and take the shot.
03-29-2007, 07:13 PM   #3
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03-29-2007, 10:10 PM   #4
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What is the price range you have in mind for a 300/f4.5 AF lens? There's the F300 and the FA300.

03-30-2007, 08:26 AM   #5
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QuoteOriginally posted by rfortson Quote
What are my options for autofocus lenses at 300mm and f4.0? AF F2.8 lenses cost too much and are too large, so f4.0 seems like the right spot. I've looked and it seems like my only option is the Sigma 100-300 f/4.0, which gets glowing reviews at FM. I guess I could have a fire sale and get rid of a bunch of lenses and such to fund this purchase, but I want to make sure I'm aware of all the options out there. What does Pentax have coming out that's in that range? Other Sigma or Tamron options? Any advice will be appreciated.
I have the Sigma 100-300 f4 EX DG lens and it's very good. I can recommend it. It is over 3 lbs and over 8 inches long, so it is rather large and heavy (but much smaller and lighter than a 300mm f2.8). There is a matched Sigma EX DG 1.4X tele-converter that gives very good results with this lens.

Another option would be a used Pentax F* or FA* 300mm f4.5, but they are hard to find and very expensive. Expect to pay more for a used Pentax than for a new Sigma 100-300 f4. You could buy a new Nikon 300mm f4 AND a cheap Nikon body for the price of a used Pentax F or FA 300!

Pentax has announced a new DA* 300mm f4 ED IF. The "targeted availability" date is "September 2007" but it will take a while to work it way to the stores. I would expect that it will be available in stores in late 2007 or early 2008. This lens will have the in-lens SDM motor for fast and quiet focusing on K10D or later bodies, but will still work with older digital cameras. It is not compatibility with film bodies. If you can wait until the end of the year, this will be the best lens in this focal length.

Finally, there is the upcoming Pentax DA* 60-250mm zoom that will be available some time in early 2008 ("targeted availability December 2007"). This might be a bit short for your needs but is another option you may consider.
03-30-2007, 08:38 AM   #6
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QuoteOriginally posted by tranq78 Quote
What is the price range you have in mind for a 300/f4.5 AF lens? There's the F300 and the FA300.
Well, since I can buy a new Sigma 100-300 for $999, I'd expect to pay somewhat less than that for a used lens. Someone yesterday (on another forum) mentioned that the Nikon 300 f/4 VR lens is around $1100 at B&H, so he expected the upcoming DA*300 to be in the same ballpark.

QuoteOriginally posted by GaryML Quote
I have the Sigma 100-300 f4 EX DG lens and it's very good. I can recommend it. It is over 3 lbs and over 8 inches long, so it is rather large and heavy (but much smaller and lighter than a 300mm f2.8). There is a matched Sigma EX DG 1.4X tele-converter that gives very good results with this lens.

Another option would be a used Pentax F* or FA* 300mm f4.5, but they are hard to find and very expensive. Expect to pay more for a used Pentax than for a new Sigma 100-300 f4. You could buy a new Nikon 300mm f4 AND a cheap Nikon body for the price of a used Pentax F or FA 300!

Pentax has announced a new DA* 300mm f4 ED IF. The "targeted availability" date is "September 2007" but it will take a while to work it way to the stores. I would expect that it will be available in stores in late 2007 or early 2008. This lens will have the in-lens SDM motor for fast and quiet focusing on K10D or later bodies, but will still work with older digital cameras. It is not compatibility with film bodies. If you can wait until the end of the year, this will be the best lens in this focal length.

Finally, there is the upcoming Pentax DA* 60-250mm zoom that will be available some time in early 2008 ("targeted availability December 2007"). This might be a bit short for your needs but is another option you may consider.
Thanks for the detailed response Gary. I should probably wait for the DA*300, but that seems like a lot of missed opportunities between now and then. I may just go for the Sigma 100-300 since it gets such good reviews and then make a decision on whether or not to sell it when the DA* comes out.

The 60-250 sounds nice, but that is getting a little shorter than I'd like.
03-30-2007, 08:40 AM   #7
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QuoteOriginally posted by Dana G Quote
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Yeah, I've considered it before, but do I have to make some allowances on exposure? I don't want to trade one complication (focusing) for another complication (exposure). I wonder why Pentax didn't use something like this when they designed the camera.
03-30-2007, 08:43 AM   #8
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QuoteOriginally posted by FotoPete Quote
Just use your eyes. Use the focus indicator as a guide. But at 300mm, I find the magnification pretty good and enough to tell if stuff is in focus.

If you can't determine focus, think of your distance to the subject as having a radius "x". Mentally 'draw' out a bit of the circumference. Or think if drawing a 'curve' with a compass. If you can find something nearby thats a bit more 'edgy' or has distinct details, focus on that, pan back to your subject and take the shot.

Ahhh, if only it were that simple, Pete. The old eyes just don't work as well as they once did. I don't just rely on the focus confirmation. I also use my eyes. Problem is, I can't tell which one works better. Sometime they both seem to agree, sometimes my eyes say I've focused, and sometimes the beep says I've focused. Therein lies the rub.

03-30-2007, 01:51 PM   #9
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QuoteOriginally posted by rfortson Quote
Thanks for the detailed response Gary. I should probably wait for the DA*300, but that seems like a lot of missed opportunities between now and then. I may just go for the Sigma 100-300 since it gets such good reviews and then make a decision on whether or not to sell it when the DA* comes out.

The 60-250 sounds nice, but that is getting a little shorter than I'd like.
You're welcome. I hope it helps.

I was in a similar situation when deciding to get the Sigma 100-300. I have a manual focus Pentax M*300mm f4, but I need auto-focus and auto-exposure to capture the fast action at my son's soccer games. (I also needed a zoom lens, which ruled out the DA* 300, but I was considering waiting for the DA* 60-250).

Comparing the image quality of the Sigma 100-300 at 300mm with the M*300, I was quite surprised at how well the Sigma performs. The M*300 is very slightly sharper, and has better contrast. But the difference in image quality is not that great. The Sigma is at it's best at f8 but it produces very good results even wide open. The matched 1.4X EX tele-converter gives excellent results, so that gives you a very usable 420mm f5.6 if you need greater reach on occasion. The Sigma will auto-focus with the teleconverter, but it's pretty slow (which is typically the case with the screw-drive AF).

What I would really like is a Pentax DA* zoom that reaches to 350-400mm at f5.6 and includes an in-lens motor. But until Pentax produces such a lens, I'm happy with the Sigma 100-300 f4. I also considered the Canon 100-400 f4.5-5.6L and the Nikon 80-400 f4.5-5.6 VR (with appropriate matching digital bodies) and they both had their pluses and minuses. In the long run, I decided I'd be better off sticking to my Pentax system with the Sigma lens, and I don't regret the decision.
03-31-2007, 03:25 AM   #10
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QuoteOriginally posted by rfortson Quote
Hey gang,
I have the SMC300 f/4.0, which is a nice lens, but I continue to have problems consistently focusing at the long end. I use focus confirmation, but I still get too many soft shots. I also have the 1.7x AF converter, and it works mostly (though it's not supposed to), but I'd rather just have an AF lens. Which brings me to my question.

What are my options for autofocus lenses at 300mm and f4.0? AF F2.8 lenses cost too much and are too large, so f4.0 seems like the right spot. I've looked and it seems like my only option is the Sigma 100-300 f/4.0, which gets glowing reviews at FM. I guess I could have a fire sale and get rid of a bunch of lenses and such to fund this purchase, but I want to make sure I'm aware of all the options out there. What does Pentax have coming out that's in that range? Other Sigma or Tamron options? Any advice will be appreciated.
I've been down this route.

I had an A*300/f4.0, but desperately wanted closer than 3 metre close focus and AF and keep similar IQ. I also had the Tokina 80-400 but wanted something better.

I bought the Sigma 100-300 EX and had issues with edge sharpness and inaccurate AF (BF and FF depending on the focal length) despite having it returned to Sigma Japan for re-callibration. I checked it on 4 different bodies and produced similar results. I also checked other examples and found them to be consistent with mine.

I finally returned it as unsatisfactory and searched for a few months and bought a FA*300/4.5. It is simply brilliant, even with my Tamron 1.4x TC.

I then sold my A*300 to another happy user. I also sold my Tokina 80-400, which I sometimes regret, but I'm waiting for the DA* 60-250.

I posted a short review of some of my initial findings here:
Lens tests by Richard Day
04-01-2007, 07:27 PM   #11
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QuoteOriginally posted by Richard Day Quote
I've been down this route.

I had an A*300/f4.0, but desperately wanted closer than 3 metre close focus and AF and keep similar IQ. I also had the Tokina 80-400 but wanted something better.

I bought the Sigma 100-300 EX and had issues with edge sharpness and inaccurate AF (BF and FF depending on the focal length) despite having it returned to Sigma Japan for re-callibration. I checked it on 4 different bodies and produced similar results. I also checked other examples and found them to be consistent with mine.

I finally returned it as unsatisfactory and searched for a few months and bought a FA*300/4.5. It is simply brilliant, even with my Tamron 1.4x TC.

I then sold my A*300 to another happy user. I also sold my Tokina 80-400, which I sometimes regret, but I'm waiting for the DA* 60-250.

I posted a short review of some of my initial findings here:
Lens tests by Richard Day

Thanks Richard. Yours is about the first negative post I've read on the Sigma 100-300. I know you're not a complainer, so I'll take that comment seriously. Do you have any examples of the problems?

Right now, I'm still thinking of getting the Sigma 100-300, unless I can get an F/FA* 300 a little bit cheaper. When the DA*300 comes out, I'll reassess my options.
04-01-2007, 07:33 PM   #12
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Oh haha I turned off the beep. Too much noise.
04-02-2007, 03:25 AM   #13
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I had the choice between a Sigma 100-300mm and Pentax 300mm F4.5, after handling the 300mm F4.5, I decided on it. Why did I do that? The Sigma was too godamn heavy to carry around practically for my case.
04-02-2007, 05:16 AM   #14
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QuoteOriginally posted by rfortson Quote
Thanks Richard. Yours is about the first negative post I've read on the Sigma 100-300. I know you're not a complainer, so I'll take that comment seriously. Do you have any examples of the problems?

Right now, I'm still thinking of getting the Sigma 100-300, unless I can get an F/FA* 300 a little bit cheaper. When the DA*300 comes out, I'll reassess my options.
Take a look at the link to my short review site (in my initial post), there are some examples of my early findings there.

I shall also up date the site with more results in the next 48 hours. So revisit in a couple of days.

It may be that the latest 100-300 EX DG's are better. I have no evidence either way. Sadly my own personal experience with Sigma lenses has been less than wonderful, i.e. a zero acceptability rate to date. Others have found otherwise, but I know I'm not alone. Therefore I am extremely sceptical when considering a Sigma, especially an expensive one.

It always pays to check the specific lens you get and ensure that you have adequate coverage for returning the lens for a full refund if it proves unsatisfactory.

It is, as someone else has stated, a huge monster, it is actually fatter and longer than the Bigma unzoomed!

Mounted on my istD



Compared to the A*300 and Tokina 80-400 (fully extended)



Sorry for the poor quality, taken with my cellphone camera!
04-02-2007, 09:50 AM   #15
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QuoteOriginally posted by Vulpix Quote
I had the choice between a Sigma 100-300mm and Pentax 300mm F4.5, after handling the 300mm F4.5, I decided on it. Why did I do that? The Sigma was too godamn heavy to carry around practically for my case.

QuoteOriginally posted by Richard Day Quote
It is, as someone else has stated, a huge monster, it is actually fatter and longer than the Bigma unzoomed!
Wow, I had no idea it was that big. I just assumed it was smaller than the Bigma. Thanks for the heads up!

I"ve heard similar comments about Sigma's quality control. I have the Bigma and find it a very nice lens for it's purposes. Also, I'm one of those guys that likes the flexibility of zooms. It's just that fast zooms are usually more expensive than fast primes of the same range. However in this case it looks like the fast Pentax prime, even used, is more than a fast 3rd party zoom new.

I'll check your pictures, Richard. Thanks again to all for the advice/comments.
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