Tamron 17-50mm f2.8 sharpness
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virtuaoski
New Member
In Sep, I bought the Tamron 17-50mm lens with motor to use with my Nikon D40. I found an issue when the lens would occasionally fail to autofocus (i.e., the lens does not even try to focus; the focusing ring does not turn at all), resulting in out-of-focus pictures. Sometimes, the camera shows "lens not mounted". This usually happens after I zoom to 17mm. And it took me a week to realise this because this problem would only happen very occasionally. I searched online and found this problem described in other forums as well.
As I found this problem within two weeks after purchase at CP, I sent it back for servicing. Since CP had no lenses on hand for exchange, they were nice enough to send it to the local service centre for me, who sent it back to Japan! It's been a month already and maybe it will take another month for the servicing to be done.
As I found this problem within two weeks after purchase at CP, I sent it back for servicing. Since CP had no lenses on hand for exchange, they were nice enough to send it to the local service centre for me, who sent it back to Japan! It's been a month already and maybe it will take another month for the servicing to be done.
Actually how do you really define "sharp wide open"? Will a copy that focus accurately qualify as "sharp wide open"?
I would like to think that a picture taken at f2.8 would be naturally not as sharp as one taken at f8 or f11. Or is my understand wrong and a picture at f2.8 can be as sharp as one taken at f8.. (leaving DoF out of the equation)?
Anyone?
I would like to think that a picture taken at f2.8 would be naturally not as sharp as one taken at f8 or f11. Or is my understand wrong and a picture at f2.8 can be as sharp as one taken at f8.. (leaving DoF out of the equation)?
Anyone?
geraldkhoo
Senior Member
Focusing and sharpness are 2 different things. Focusing issues talk about how the camera determines the correct focus, so if you have front or back-focusing issues, the point you want to focus on is soft, but the sharpness is front or behind the place of focus.
Sharpness talks about how the lens resolves and whether you get a sharp pic or not depends on the lens. Yes, at f/8 to f/11 tends to be the sweet spot for the sharpest image, so f/2.8 would not be as sharp as at f/8, but you can have varying degrees of sharpness at f/2.8 with different lenses. I can say that the sharpness of the Tamron 17-50 f/2.8 lens (the one I own does not have the in-built motor) is as sharp wide open as the Nikon 17-55 lens.
At the same time, f/2.8 would have a thinner depth of field, so the depth of the focused area would be thinner than at f/8, and sharpness is not to be mistaken for shallow DOF.
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Yea, it does make sense if we are comparing two pictures taken at f2.8 but from lenses of different makes. However, most of us typically do not have the luxury of having 2 similar lenses to compare side by side and that is also why i posed my question earlier on.
I also do know about the shallow DoF that comes with f2.8 but i think that if we just compare the image qualities of a f2.8 shot and a f8 shot (at the planes of focus), the f2.8 image should be a little softer than the f8 shot.
Well, i guess the alternative will be to look at 100% crops..
this link might help check the focusing http://focustestchart.com/focus21.pdf
Also interested to know if calibration is free if under warranty
Also interested to know if calibration is free if under warranty
psychobiologist
Senior Member
yes the centre AF point is the most sensitive.... the ones on the peripheral are less sensitive.. you need good contrast at these sites too
Are they able to confirm focusing error here? Did you finally sent it in? I am thinking of doing the same
Sorry, I didn't ask about focusing issues as mine was a sharpness issue.
I haven't sent it yet. I can't afford not having a lens for 4 weeks.
Try calling them to ask. JEL Corp: 6248-5333
thanks for the info
Could be a BF or AF problem. I got mine with a little BF, but it got worst after a few months of usuage.
I got mine from ShaShinKi, was kinda lazy to send to Malaysia. So email JEL and ask if they can help, they replied me saying the lens needed to be sent back to Jap and cost about S$140. End up I send it back to ShaShinKi, ShaShinKi then send to Tamron Jap. The whole process took less than 6 weeks for the repaired lens to come back^^
I got mine from ShaShinKi, was kinda lazy to send to Malaysia. So email JEL and ask if they can help, they replied me saying the lens needed to be sent back to Jap and cost about S$140. End up I send it back to ShaShinKi, ShaShinKi then send to Tamron Jap. The whole process took less than 6 weeks for the repaired lens to come back^^
did it improve your AF after repair?
Tack sharp at f2.8 with sufficient light^^
This was when I 1st got the Tamron 17-50mm f2.8, testing to see how sharp the Tamron 17-50mm f2.8 is at 50mm f2.8
100% cropped
shootsimon
Member
Can this lens use on a full frame body?
Blur Shadow
Senior Member
Nope. The Tamron SP AF 17-50mm F/2.8 XR Di II LD Aspherical [IF] (Model A16) is designed for the DX format, as are all Tamron lenses that are designated Di II.
Hence, it should not be used on a full-frame body, although you can certainly try. It will work up to a certain focal length, I believe.
Hence, it should not be used on a full-frame body, although you can certainly try. It will work up to a certain focal length, I believe.
shootsimon
Member
Thanks!
Tack sharp at f2.8 with sufficient light^^
This was when I 1st got the Tamron 17-50mm f2.8, testing to see how sharp the Tamron 17-50mm f2.8 is at 50mm f2.8
100% cropped
AF looks pretty good already when you first got it. Cann't imaging how good it must be now. Looks like it is a good idea to sent it in for calibration.
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