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03-25-2012, 04:40 PM   #1
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bad lens?

I just purchased a used DA L 55-300mm, and I am a bit concerned. I can't tell if the lens is just that soft, or if it can't quite reach infinity. Would someone be willing to post a picture or two taken with their 55-300? What I am looking for is full 300mm, wide open aperture, a subject with sharp edges far enough away to be at infinity focus. For example, I am trying to focus on a building located about 350 feet/106m distant that has vertical bars supporting a deck rail and horizontal clapboard siding.

I can focus as close as approximately 6 feet/2m - on a measuring cup - with nearly 1:1 size sharp text and lines. But even using manual focus and focusing all the way to the stops, long distance subjects seem a tad fuzzier than I would expect. I need to make up my mind about this lens in short order, so I am hoping some of you kind folks can help.

03-25-2012, 06:34 PM   #2
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Jim, from your signature you have been pushing camera buttons for awhile so apologizes if you already checked this. The DA 55-300 is just so cute and little that I sometimes forget that it is a 300mm lens. So I let the shutter speed fall off without noticing and I start to get images less sharp than I would expect. Wide open at 300mm you need 1/1000th to hand hold (well I do, maybe you are better) or a tripod. Try that and see if it improves things. If not, it is possible you got a bad copy or it needs calibrated to your camera. With the k-5 you can adjust the AF per lens, not sure what camera you have though.
03-25-2012, 07:23 PM   #3
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Hi Stormtech-
I somehow doubt you were focusing at infinity - that or you have scary big squirrels roaming around your house. I suspect I have a bum lens that is not capable of reaching infinity. I get nice shots closer in.

Hi jatrax-
Thanks for the cudos. Yes I supported the camera. I have a K-r and had previously adjusted the slight front focus using my 18-55 at around 28mm. The K-r (to the best of my knowledge) can only store one AF adjustment. However, I ran my tests at 300mm with the viewfinder AF, the LCD AF (which uses a different system), and manual focus again using both the viewfinder and LCD. The results are consistent for all 4. Focus seems way too soft on long shots.

Before I accuse the seller of trying to palm off a lens that is incapable of infinity focus, I want to see what others can produce with this model lens.
03-25-2012, 08:55 PM   #4
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Are you using a UV or 'protection' filter on that lens?
Also shoot at about f8 or f9 to see that lens at its sharpest.

Close in this lens can get good detail and colour like this:


Juvenile Pied Butcherbird portrait 2

At infinity focus, perhaps look at the original size of this panorama:


Corin Road panorama 1

The DAL 55-300 is no Zeiss, but it is normally a perfectly OK piece of glass.

03-26-2012, 08:42 AM   #5
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Thank you rawr- your landscape photo helped me find the problem.
Indeed the lens was not quite reaching infinity. I suspect dust or the like in the focusing helix. I crossed my fingers and used some air from a partially emptied can for reduced pressure and give the lens barrel a couple short bursts. I then manually (off camera) moved the focusing ring back and forth. The next trial at the same target produced MUCH better results.
03-26-2012, 09:52 PM   #6
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QuoteOriginally posted by JimJohnson Quote
The next trial at the same target produced MUCH better results.
Glad you got it worked out. That is a great little lens, I never leave home without it.
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