Pentax SDM vs. Sigma HSM - speed?

<p>Does anyone here have experience directly comparing focus lock and tracking speeds between a Pentax SDM lens like the DA* 50-135 and a similar Sigma HSM lens like their 50-150 or 70-200 EX f/2.8 lenses? I've been wondering for a while how much faster Sigma's true ring style ultra sonic HSM focus motor is over our Pentax SDM micro motor lenses.<br /><br />I was shooting some amateur softball this weekend and got a little frustrated with focus lag on my K20 and DA* 50-135. I used to own the Sigma 50-150 DX in EOS and it was considerably faster at locking focus. But I've no idea how much of that was the Canon body and how much was the the lens' ring style ultrasonic focus motor.<br /><br />Is there a noticeable focus speed difference between Sigma's HSM and Pentax's SDM lenses?</p>

<p>Hey Roger,<br>

If you wanted fast AF then you should have never switched to Pentax. That is one of the few things that are done badly here. I'm sure you know what a superb lense the DA* 50-135 is since you've used it. Unfortunatly Pentax decided to go cheap on the AF system. My take is that part of the problem is that Pentax uses a really old AF system in it's top of the line DSLR's and cheap SDM motors to top it off.<br>

I hope you got the extended warranty on your DA* as they're nutorious for SDM failure.<br>

Considering that you could have bought a EOS 40D/50D for the same price as a K20d... do you feel that the benefits that the K20d offers outweigh the shitty AF performance and burst rate?<br>

I recently got a chance to play with a Rebel XT and Sigma 17-50 F2.8 HSM. I dare say that it would beat a K7 and 16-50 SDM in an autofocus performance test.</p>

<p>I used to shoot a lot of basketball, and I remember how frustrated I would get using the 50-135 on my k-20d and then k-7. I found I needed to switch to screw drive primes to get AF speed I could live with. I agree with Martin about Pentax AF speed, as well as SDM. I have since had an opportunity to test an EOS 550D (t2i) as well as a 7D in a variety of environments. The AF speed and accuracy was so much better on the EOS cameras equipped with ring-USM lenses, that it is hard to go back to shooting Pentax. Someone posted a video on youtube that shows a 20-year old EOS camera with an old kit lens focuses faster than a new k-7 with a kit lens. (search for Pentax vs Canon on youtube). I could live with it for most situations though.<br>

One thing is for sure; I have owned my <em>last</em> SDM lens.</p>

<p>Matrin and S thanks for your comments on the Canon gear. I had an EOS Xti and 30d plus about five EOS USM/HSM lenses for about 18 months. I really, really tried to like them, but I hated my Canon gear. The size and bulk, over prices stabilized lenses, cracker jack build quality on the Xti and marginal build on lenses until you get into the "L's" and the body ergonomics made using them much more a chore than a pleasure; Canon was so not a good fit for me. I'm normally a social event / wedding and travel shooter. For me Pentax is a better fit in most ways. </p>

<p>Recently I have been "corralled" into shooting some amateur sports. If I really get into this and can somewhat monetize it I "might" consider adding a Nikon body; but I really have no interest in changing or adding another system. </p>

<p>My question is really specific to Pentax SDM body ownerswho have shot with a Sigma HSM lens. Is there a noticeable difference in focus speed?</p>

<p>Martin,</p>

<p>First, I believe SDMs do have a higher rate of failure, however, I have had my 50-135 since it's release date, and no failure.</p>

<p>Occassionally it locks up where the SDM doesn't turn, a friend of mine bought a used 50-135mm without a functioning SDM motor and came up with this fix.</p>

<p>Rotate the focus ring from near focus to infinity a few times, voila AF works.</p>

<p>I've only had to do this 1X but it fixed the issue. I have a feeling it has something to do with the dual focus system.</p>

<p>Roger,</p>

<p>I own Sigma HSM with Nikon mount, and my experience with the Sigma is they are nearly as fast as nikon, but just a little slower.They are definitely on par with Nikon screw drive lenses on a high end body.</p>

<p>It's hard to compare Nikon to Pentax, but I'd say the 50-135 is significantly slower. I didn't find the 200mm or 300mm to be particularly fast either.</p>

<p>That said, I found them functional for sports and action. I think they are faster than Pentax screw drive because they can reverse faster, but remember, comparing Pentax to other brands is tough because of the Pentax stutter confirmation.</p>

<p>What is comes down to is IQ to me, the SDMs are fast enough, but do you value focus speed over IQ? And that isn't a knock on Sigma, it's well known I have a few Sigma lenses I am fond of.</p>

<p>As far as sports, work on your technique. If you find yourself chasing the action and needing FPS and focus speed to keep up, your not doing a good job. Unfortunately it's just a misconception on how pros shoot. I was recently looking at a 3rd party battery grip for my K-7, and I ended up reading all the reviews on the D300 version (which was stellar overall), anyway most people shooting sports admitted they didn't really care about the FPS boost, although they were jazzed the 3rd party grip gave it to them for $80, it was more about the full secondary control layout.</p>

<p>I really can't recommend enough sitting with some pros sometime and seeing just how controlled they shoot action. Single frame, and they know where they want to be. Believe me, you start firing off burst of 10 shots, and you are gonna get some dirty looks, maybe even a snide comment or two.</p>

<p>Anyway, people take clinics on strobing, and landscapes, but they assume sports is all about the equipment and how fast the camera is, I'd venture to say being a good sports photographer is equally hard as being a good ______ (fill in the blank) photographer. </p>

<p>That said, if you don't mind buying into two systems, going with Nikon for sports sounds like a good plan. However, you may end up in my position, wishing you'd just invested the money into your Pentax kit. If I had back the money I spent, I'd have bought a DA 200mm or Sigma 70-200, K-7, and a DA 300mm along with the Tamron TC that goes for insane cash on ebay.</p>

<p>The problem was 2.5 years ago, when I invested in Nikon, Pentax didn't have these lenses and Sigma didn't either. And cashing out of Pentax could have been profitable had I just made a cold switch, but as I've noted all along, while Pentax doesn't have the lens lineup of Canon and Nikon, Nikon doesn't have the lens lineup of Pentax. Essentially Pentax is screwing me by being niche.</p>

<p> </p>

<p>I agree with Justin's comments. I am certainly not a pro sports photographer- far from it. But I also rarely shoot bursts when I do shoot sports action. Maybe I am just more conservative in general from my years of film shooting, but I get a fair percentage of in-focus keepers, from an angle I was after, without resorting to spray and pray.</p>

<p>I can say for sure that my Sigma EX 24-60mm f/2.8 produces faster AF performance for me on either my K200D or my K20D than some other lenses I have used. But it is not HSM. It seems to me that a number of factors in lens design go into how fast the AF will perform. One is the degree of rotational travel. A somewhat greater rotational travel will be an advantage for fine tuning MF, but a disadvantage for AF speed. A case in point is the Pentax DA 55-300mm, which has considerable rotation and a decent MF feel, but is just a bit on the slow side for AF. </p>

<p>Hello,<br>

This is my first post and I promise to follow up with an intro later but had to respond to Justin's comment above. This is somewhat off the OP's topic so I apologize if that is a no-no here but its related. The Tamron TC that Justin said goes for "an insane amount on ebay". The only Tammy TC that works with SDM is the 1.4x Pz MC4 which, at least on the PentaxForum Marketplace, typically goes for $120-140. I am about to list one there for that range also. But the TC I recommend for sports and birding with ANY lens using Pentax body is the Pentax AF 1.7x. Its available used on ebay or NEW through brokers in Japan or PentaxForum member TOM1803 who lives there and resells them on the PF marketplace.<br>

Why this TC? Not only does it autofocus ITSELF but it only works in a short range so if you miss with your AF point while following action it can cycle in a fraction of the time that your lens can. I don't shoot sports so may not know all the issues but for fast moving critters I use it with the DA*300/4 handheld and manually set the focus approximate then let the TC AF take over. At F6.3, the TC can handle the focus from about 50m to infinity with my setup. At much closer subjects like my feeder at 8m, the TC range is only about 1-2m...perfect for following the action of birds landing and leaving the feeder. <br>

My point is it is MUCH faster to work with than the Tamron 1.4x (I have both) because the penalty for missing the focus is so short. Yes, it costs 2.5x as much but once you have it the Tammy sits on the shelf. If I had to equip for shooting the kids soccer or field hockey I would go for the DA*200/2.8 plus the AF 1.7x TC.<br>

Last, I agree with the OP that SDM focus feels slow. My DA*300/4 is everything I want in a 300mm prime EXCEPT its AF speed. I will be trying out an HSM Bigma when I can rent one for a month and then choose between speed and IQ.<br>

Lee</p>

<p>Thanks for the comments guys. I agree technique has more to do with success in sports (and any other style of photography) than equipment; which is why I'm resistant to suggestions of adding or changing systems. I'm usually a center point, focus lock, recompose, single frame shot guy. In 2.5 hours of softball I shot about 150 frames and the teams were thrilled. But I felt frustration in getting a focus lock fast enough even with anticipating action. In all fairness to Pentax AF I did have some fencing I was right up against between me and the players most of the time, which was no doubt not helping my AF. Next week I think I'll get there early enough to talk to the umpire about getting on the field near the first base line dug out. But this was far from the first time I've felt the DA* SDM was too slow to lock focus. I took the DA*50-135 and my Bigma. Next week I'll just take my recently acquired Tokina 70-200 f/2.8 ATX. It should be all the range I need and I've yet to give this lens a proper work out. I'm still rethinking lenses and what's staying and what's going which is why I've been wonder if HSM is significantly better than our SDM. </p>

<p>@Justin regarding Sigma EX lenses and IQ compromises. As I mentioned I owned the 50-150 EX in an EOS mount and IQ wise it's exceptional, optically every bit as good as our 50-135mm. With the Sigma you get closer focusing and lose weather sealing. I have no real complaints with any of the Sigma EX lenses I've used except the 10-20mm which I was disappointed with after the EOS 10-22. I've yet to buy a K mount rectilinear ultrawide. My only "complaint" with Sigma EX lenses is the zoom/focus rings move backward compared to Pentax, which should be a minor thing but it bugs me. I don't understand the IQ compromises you're referring to. I do remember the color rendering being a little cooling, but not sure if that was the Sigma coatings or the Canon sensor but it's easy enough to warm up.</p>

 

<p>Roger,</p>

<p>I have no issues with Sigma. However, Pentax contrast is usually better, so is flare control. Colors tend to be a little better.</p>

<p>That said, I am the very happy owner of 3 EX lenses, and 1 non EX. And I will continue to buy Sigma glass when I see lenses that have that price/quality ratio vs. pentax.</p>

<p>But I think when it boils down to the utmost IQ, Pentax is definitely (overall) a bit ahead of Sigma on most lenses.</p>

<p>I agree, Sigma is generally a level below the lenses of Nikon, Canon - or Pentax (from my limited experience). They often compromise in areas like size, but not always. The EX standard is usually very high, but things like wide-open performance and build quality is often behind the real top lenses of other brands. Perhaps less behind than some people think, in my opinion. They're usually a lot cheaper. They can't match the best of the other brands, but come close to a greater or lesser degree.</p>

<p>In saying that they occasionally come out with real beauties optically. The 100-300 f/4 is often noted as one (and noted for good AF speed, although the Pentax version is screw drive only). I think their 50mm f/1.4 is getting the same reputation for good optics.</p>

<p>Can't really help with your original question as I've never used an SDM lens. I have one Sigma HSM, and it's good on the K-7, but not as fast as Nikon's motor drive (on Nikon body).</p>

<p>@ Lee: I share your enthusiasm about the FA 1.7 TC, especially in combination with the DA*300mm. I've never used it for fast-moving field sports like field hockey and lacrosse though, figuring that the two-step (AF/MF) focusing would be impossibly frustrating where distance-to-subject changes very quickly. Apparently you have not found that to be the case?</p>

<p> </p>

<p>Sorry for the late reply. I've been testing the Pentax 60-250/4.0 against the Sigma 70-200/2.8 HSM and the Tamron 70-200/2.8 (non-HSM) and was impressed by the speed of the Tamron. It locked focus much faster than the Sigma which was hunting a lot. The Pentax however was a different league, but you pay for it. A while later I did a quick test on the 50-135/2.8. This is a really nice short and fast lens, but still comes with quit a price tag.<br>

It was only a short test, bit I think you have to go to a shop where they have all the lenses you're looking at and just try for a while. It was only a short test for me, but the outcome amazed me, I really liked the Tamron!<br>

By the way this was done using the K10D with the latest firmware.</p>

<p>@ Dave - For fast moving subjects like birds, I get way more keepers with the FA 1.7x on my DA*300 than just the lens itself. Now if its coming head on, I am not good enough to anticipate and get sharp focus regardless of equipment. But an Osprey moving from right to left at 75m is well beyond the equivalent of the Hyperfocal distance of the TC at my typical focal length and as I said, my AF miss only costs me a fraction of the time that the lens alone does. Same for very close semi-still shots like the feeder. My AF miss with the DA*300 cycles forever since the background is 100m away and the feeder is 8m. But the TC only has a range of about 7-9m so it tries once and if the bird is not in that range I move the manual ring a bit and bingo. <br>

Just my experiences, a real photographer can do better.</p>

<p>Lee W. You won't make it as the DA300mm+1.7TC has given you very very little DoF to work with. Manual tweaking while doing AF is an idea but hardly anybody has done it for fast subject<br>

[[[[Lee W:At F6.3, the TC can handle the focus from about 50m to infinity with my setup. At much closer subjects like my feeder at 8m, the TC range is only about 1-2m...perfect for following the action of birds landing and leaving the feeder. ]]]]</p>

<p>This is my 1st time on photo.net been reading posts for about a year. I'm kinda shy. nevertheless, I been using pentax (k100d super, k200d, k20d,and now k7) for about 3 years and quikely moved up the latter. But found with each step that the only thing that never changed was the auto-focus speeds. My k-7 has 5.2 frames per second and I shoot mainly wildlife and birds. whats frustrating is that 5.2 frames per second is great, if you can't lock focus fast enough on moving subjects, it doesn't mean a thing. I recently shot my grandsons tee-ball game with my (favorite lens) da* 50-135, color and contrast where amazing. I got very frustrated at the sluggish sdm. I have the sigma 100-300 ex dg and by far it's the best iq and fastest lens I own. it serves me well for wildlife, but sometimes scares away my subject. Getting to the point, I'm also looking for a quite, fast, good iq mid range tele for such situations. my 50-135 is really my portrait lens. and the 100-300mm is to long heavy for inside sports and tee-ball games. my belief is the hsm will have better auto focus speed than the sdm, both my sdm lenses are fairly slow. again, is it the tamron 70-200mm or the sigma 70-200mm lens, that is the question?</p>