I don't get a focus confirmation with distant objects. Set the lens to AF, let it go to the intersection and it just hammers against the infinity stop.
Set it to MF, f8, put it so the camera will fire, take a shot:
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| From 24 experiments |
Crops:
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| From 24 experiments |
Those look right to you? The grass near the bottom 1/4 line of the shot seems to be the sharpest thing.
Unfortunately, I can't find full-size sample shots ANYWHERE. Photozone guy didn't upload test shots, and none of the people on pbase with this lens uploaded anything larger than about 800x1000, so I don't know if this is typical for this lens.
ReplyDeleteIt looks pretty bad.
ReplyDeleteThe lack of focus confirmation at infinity is not that concerning, I seem to recall that being an issue with wider lenses (although on a crop camera this shouldn't be wide enough for it to happen), particularly Canon's 10-22. Plus, it could be a scene issue, since autofocus is still voodoo, even today.
But those Coke cans (now knowing the focus point) are problematic. I'd bring the lens inside, cool it down, and check again in the morning. If it is still off by that much, send it back. That isn't the typically "wah wah my $1500 lens is off by 0.5mm, that is off by INCHES. I'm impressed the camera can even compensate for that much back focus. Then again, the adjustments must be pretty coarse, which doesn't look good for minor problems.
Incidentally, my 10-22 hunts at infinity on my XT, but not my 40d. My 50 hunts at the close range on both. My 100-300 hunts on both just above the cutoff for the macro disable switch. My 400 hunts on both with the outer focus points. My 17-40 never hunts.
ReplyDeleteAs I said, autofocus is voodoo.
Yeah, the adjustment range is a sweep of twenty "steps" from "adjust to behind where you think you should" to "adjust to in front of where you think you should." I honestly don't know what the right answer is, because it seems to be between 7 and 10 but neither 8 nor 9 is very good either, and I'm thinking that's because the lens must have been kind of beaten on.
ReplyDeleteConsidering you don't usually buy a lens like this to use it at f8, that's not really a very good solution, and ... well, I mean, I could put it on a tripod and see what 8 looks like at about the same subject distance of the cans, but what's it going to prove? In the field, the lens is kind of annoying, it turns out.
I'm going to take a couple pictures of people or something tomorrow, then probably call KEH and get an RMA. A 600 dollar piece of equipment needs to be more consistent than this.
Interesting aside - when the lens was discontinued in 2004, it was apparently selling for $580 or so new. This means it's one of the few Pentax lenses (especially * lenses) that has not had a sharp increase in price since it stopped being produced and the K100D was introduced.
In some ways, I hate the K100D for what it did to the Pentax market, but at least the new lens designs keep coming.
I have some problems at distance with uh... well, probably the 77 or 43, since those are going to be the ones with the weirdest contrast wide open where focusing happens, but not with any of the other AF lenses I've used.
ReplyDeleteFor the record, the K20D does support SWM, but I don't have any lenses that use it. The FA 24 focuses its entire range pretty much instantaneously, it's kind of amazing how fast it goes. The 43 and 77 take a while to rack, which is good because I use those as MF quite often, the 14 is relatively fast again due to short throw, my 50-200 has a long throw and seems proportionately slower than the others, and the 16-45 is about in the middle of everything.
On the 24 earlier, I wasn't getting focus confirmation until I came down a hill to somwhere between 30 and 50 feet away from me. It was kind of embarrassing.
I hate to say it, but I'm glad I ditched Pentax. They make some interesting cameras, but their lens support is such a mess with the old and new lens lineups screwing with the market.
ReplyDeleteUsed gear is always a crapshoot. I had to return the first 100-300 I got due to a loose zoom and bum focus. That lens is odd, because it has a telescoping zoom mechanism that pumps rather than turns, and it tends to drift when pointed up. The autofocus only worked over part of the focus range. Keh sent a good replacement, although they cheesed me on a lens cap in the replacement. I also had to return a Canon film camera to Adorama.
Then again, it could be a bum model. Most manufacturers have made a few.
I went birdwatching, saw nothing of interest, and got scared away by the coyotes. Darn things are everywhere these days.
ReplyDeletejosh -
ReplyDeletedunno what you mean about pentax and lens support - oh, wait, i have a 6x7, where all the lenses work on all the bodies just fine over a decades-long span.... too bad they stopped making the things tho, oops.... i need to hunt down a 105/24 and one of the longer f2. lenses for that thing soon, maybe after i sell some more junk to add to the toy fund tho.
-GMT
GMT,
ReplyDeleteI think the Pentax lens issue is multifaceted. Nikon has had a similar history of body interaction over decades of lens lines, and their lens market isn't as crazy. Even the fact that both had a rocky transition from manual focus, to in body autofocus, to in lens focus isn't really a big deal, but contributed by making some lenses more desirable for certain people.
I think the big component is that Pentax had a huge boom many years ago, along with a huge boom of third party lenses and cameras, and then died off for a while. Their production dropped, and even now with their renewed popularity, they are struggling to make lenses fast enough. This creates unusual demand for their old lenses, even manual focus lenses (which used to be dirt cheap), and pushes their new lens prices up.
I should also mention though that Pentax lenses are a great thing to have to sell, if you own them, since they've probably appreciated in value significantly. I bought several manual focus lenses before Pentax's dSLR line came out, and sold them a few years later. All of them had appreciated, and none of them were even genuine Pentax gear.
ReplyDeleteI should also mention that Canon has some odd ducks that don't behave normally on the used market. They are all lenses that have either been discontinued but fill a gap Canon abandoned, or are lenses produced in stupidly small numbers despite their popularity. I own two such lenses, the 100-300 5.6L and the 400/5.6L. The 100-300 is long since discontinued, but has really good optical quality despite weird ergonomics and old fashioned autofocus, so it remains surprisingly popular on the used market. They tend to move within a day or so at KEH if in good condition. The 400 is an early USM design without IS and with a slow aperture, but it is the longest lens most non professionals are willing to splurge on. Canon reported makes only a few thousand, at most, in a given year. They sometimes move within hours on KEH, and the price varies considerably depending on if they are available new and how many are out on the used market. There is another lens, I think an exotic glass (even for an L) 1.2 variant of some lenses, that remains popular despite replacement.