Tamron 28-75 2.8 for Nikon D90

GemGem

Hi!

I purchased this lense about 6mos ago. I liked it at first, but then it started giving me unreliable results ( sharp sometimes, others not, focus problems, etc).This week, I decided to take it out and really play with it.

I am not sure if I have a faulty lense or if the lense is supposed to be like this, or maybe it may be my technique. Here is what I am experiencing.

f4 focal length: 40-50 and 75 nicely sharp at the center, but gets soft at the edges.

I took a set of pictures where the composition I wanted didn't allow me to use the center focus, so I selected the corresponding focus point on my camera. I know I focused on the eyes, but the pictures came out soft everywhere. Focal L was 68, f4.

#1

#2

#3

#4

#5

#6

#7


Thanks everyone for sharing your input and experiences.
GG

pathfinder

Generally the Tamron 28-75 Di is well regarded.

At f4, you will find the lens a bit sharper centrally, than in the corners. This is typical, at larger apertures, of even the very best lenses to a certain degree.

When discussing lens sharpness, hand held images are not really the best way to discern lens quality issues. Tripod and remote shutter release are more useful for this.

Are these shots jpgs? OR did you shoot in RAW? What was the ISO, and shutter speed?

If shot as jpgs, what is you incamera sharpening set at? You might want to bump it up a bit.

Some of these look under exposed a bit to my eye. #s 3,4,5,6,7 look sharp here as web size images. Check you shutter speed, kids do move. I prefer to shoot kids with at least 1/125th sec....

GemGem

Hi Pathfinder,

Are these shots jpgs? (yes, jpgs)OR did you shoot in RAW? What was the ISO (400) Shutter from 1/200 to 1/1600

If shot as jpgs, what is you incamera sharpening set at? (normal) You might want to bump it up a bit.(I will try that)

Some of these look under exposed a bit to my eye (yea, it was really sunny, so I stopped it down a bit it was clipping a lot.) #s 3,4,5,6,7 look sharp here as web size images.

#5,6, and 7 look really soft to me and #1-4 look sharp. are my eyes boggin' out?

Thank you!
GG

ziggy53

GG,

All of these images are either back lighted or in shade. The face has very flat lighting on it and that reduces the amount of shadows and facial contouring. I suspect that is what you are seeing and wondering about.

This would be a good opportunity for an off-camera flash, typically used to throw more interesting light on the subject and add interesting shadows.

You could also look for more interesting lighting situations such as open shade but with large bulbous and spreading clouds behind you to act as sunlight reflectors.

Alternately, you could shoot in fairly bright sunlight and use an external flash with FP/HSS mode to allow an exposure that trims/controls the daylight and uses the flash for fill.

I think that the lens is sharp in that I see individual strands of hair and the lettering on the girl's top is sharp. Now you just need some appropriate and controlled lighting to match.

GemGem

ziggy53 wrote:

GG,

All of these images are either back lighted or in shade. The face has very flat lighting on it and that reduces the amount of shadows and facial contouring. I suspect that is what you are seeing and wondering about.

This would be a good opportunity for an off-camera flash, typically used to throw more interesting light on the subject and add interesting shadows.

You could also look for more interesting lighting situations such as open shade but with large bulbous and spreading clouds behind you to act as sunlight reflectors.

Alternately, you could shoot in fairly bright sunlight and use an external flash with FP/HSS mode to allow an exposure that trims/controls the daylight and uses the flash for fill.

I think that the lens is sharp in that I see individual strands of hair and the lettering on the girl's top is sharp. Now you just need some appropriate and controlled lighting to match.

Oh goodness! Thanks Ziggy. I will try it with Flash and or a reflector. It is just so weird. Sometimes the camera shows me a correct exposure but the results is an overblown picture. It just happens with this lense above f4. I have been reading about it and it seems to be a known problem. I just have to check with Tamron and see if they can fix it or if that is it. Unless Dgriners have some other tips for me.

Thanks.
GG

pathfinder

GG,

If you find exposure if off due to a malfunctioning light meter, you might consider shooting by the Sunny 16 rules when shooting out of doors, in Manual mode.

Or you could invest in a hand held incident light meter that will be more accurate than the reflected meter in your camera.

Using the histogram on your camera can be a great aid in exposure also

Learning to shoot in RAW and filling the histogram - so called shooting to the right - can be a big help also.

Instead of a flash for fill light, you could also use a reflector to redirect sunlight into your subjects face. This might be challenging for shooting children, however. Flash will be much easier for moving children,

GemGem

pathfinder wrote:

GG,

If you find exposure if off due to a malfunctioning light meter, you might consider shooting by the Sunny 16 rules when shooting out of doors, in Manual mode.

Or you could invest in a hand held incident light meter that will be more accurate than the reflected meter in your camera.

Using the histogram on your camera can be a great aid in exposure also

Learning to shoot in RAW and filling the histogram - so called shooting to the right - can be a big help also.

Instead of a flash for fill light, you could also use a reflector to redirect sunlight into your subjects face. This might be challenging for shooting children, however. Flash will be much easier for moving children,

Pathfinder,

Great information, thank you!