Lens calibration?

[Leif]

Earlier this year I bought a Nikon 24-85 AFS lens as a cheap general purpose zoom. It was on offer at Warehouse Express. Net reviews are universally favourable. Sadly it is soft at all apertures and focal lengths. I compared it to my 28-105 AFD and 75-150 F3.5 lenses and IMO it is unuseable. Has anyone else had this sort of experience? I was going to sell it on WPF, but after testing the lens, I don't think I can do that as it is worse than I thought. (I also found that half the images taken in the field were extremely soft and half slightly soft, which I cannot explain since I use MLU and a tripod.) I have heard about Nikon and Canon re-calibrating lenses. Does anyone know anything about this? I assume this is re-collimating the optics. I will contact Nikon as I think a lens should be useable.

[Don Hoey]

I would agree with sending it to Nikon. I have also read the reviews and so can only assume as there is always some variation between samples yours is unfortunately not the best. I am sure that Nikon UK can correct the fault.

I would suggest setting up some form of test target and enclosing prints that would demonstrate the softness you are experiencing.

I am going through my manual focus lenses that way, as limitations will show up easier on test targets than in a scene. I used a download of the D2X target from DPR camera review.

Pic of my setup attached.

Don

[Leif]

I photographed a book shelf although it's not an ideal test as the distance is only 2m or so, and there is the issue of getting correct focus. But I'm sure it is soft. I've added two attachments taken at 85mm and F11. The image is 100% and cropped from middle left i.e. towards the edge, but at F11 edges should be okay.

I notice you have the 28-105mm zoom. Are you pleased with it? I picked one up cheap and it seems nice if a bit long at the wide end.

[Don Hoey]

Leif

The pic shows definate softening at the edges. On thing I found on my M/F lens tests was to use the electronic rangefinder ( green light ) as it is more accurate than using the focussing screen alone. So for my A/F lenses I let autofocus do the job.

Re the 28-105 it is a super lens on a 6mp sensor. I think most of my camera pics in the gallery were taken using it.

12mp does show up weaknesses. So far I have been checking my M/F lenses against the 80-200 f2.8D ( 2 ring version ). 55 Micro and 105 f2.5 are as good and are now on the A list. The 28mm f2.8 shows some colour fringing towards the edges and the 28-105 image is generally cleaner. 18-35ED f3.5-4.5 at f8 to f10, between 24 and 35mm has been amazing. Detail in the image that was not visible to the naked eye. I have not yet tried it at 18mm.

As it is now 10/10 cloud cover I will do a couple of test shots with the 28-105 and post later.

Don

[Saphire]

Don Where did you purchase your test targets from. They look a good tool for checking lenses every so often.

[sassan]

Leif;
You had no UV or any other type of filter over your lens, did you.
I had this problem personally and found why those good deals I found on ebay are so cheap...

If none, contact Nikon directly. Most likely they will ask you to buy the more expensive lenses but it won't harm and actually there is a little chance something good may come out of it.
A good Nikonphilic friend of mine got disappointed on the new sensor of D200 that could not render purple color as accurate as his D70, to make a long story short, after several extensive contacts, he was told to tolerate the new purple color...
If you didn't get the answer you want, then pay attention to your target by listening... Calm and relaxing, definitely not s o f t .

Wish you luck.

Sassan.

[Leif]

Originally Posted by sassan

Leif;
You had no UV or any other type of filter over your lens, did you.
I had this problem personally and found why those good deals I found on ebay are so cheap...

If none, contact Nikon directly. Most likely they will ask you to buy the more expensive lenses but it won't harm and actually there is a little chance something good may come out of it.
A good Nikonphilic friend of mine got disappointed on the new sensor of D200 that could not render purple color as accurate as his D70, to make a long story short, after several extensive contacts, he was told to tolerate the new purple color...
If you didn't get the answer you want, then pay attention to your target by listening... Calm and relaxing, definitely not s o f t .

Wish you luck.

Sassan.

No there was no filter. The lens is a lemon!

Don: I have the 28mm F2.8 AIS and yes it has purplies on a D200. I tried the 28-105mm in the field today - only test shots - and it performs very well once stopped down a little.

Leif

[Don Hoey]

Leif

Here is my rough test. Ideally the chart should be on drawing paper off a CAD system, but hey ho no such facilities available. The target is a downloaded version from the D2X test in DP Review. As I do not have matt photo paper this was printed on standard A4 paper. The ' macro ' shot gives an idea of the print quality and represents 70mm of the target. The full size image is 4288 x 2848 pixels.

It should also be noted that I do not yet have my remote release and although ' mirror up ' was used the shutter speed was 1/80 sec at ISO200 and the shutter hand triggered. My geared head does not ' lock up ' like a standard 3 way head.

Due to the number of pictures I am splitting this over 2 posts.

In this post the first image is the Target showing the areas selected as edge and centre, the second the 28-105 zoom at 105mm in ' Macro ' mode and lastly crops from the best lens I have - Nikkor 80-200ED 2.8. All test pictures were at f8. NO sharpening has been applied.

Don

[Don Hoey]

This post has the 28-105 at three focal lengths. 105mm, 70mm and 28mm.

For the benefit of other readers of this thread I should mention the relative costs of the 2 lenses involved. 80-200ED 2.8 UK price £799, and the 28-105 £295. As previously mentioned a lot of the D100 pictures in my gallery were taken with the 28-105, so with the D100 this lens was really like a swiss army knife. Wide zoom range and 1/2 size ' macro ' facility and good image quality.

From this Leif I would say the 28-105 is better than your 24-85. On the D200 I would say f8 - f11 would be the optimum apertures. Beyond f11 you will find the lens going gently softer and if you combine that with the effects of diffraction, images will get soft. On 6mp this will show at f16 and beyond.

Don

[Don Hoey]

Originally Posted by Saphire

Don Where did you purchase your test targets from. They look a good tool for checking lenses every so often.

Christine,

I thought I would go one better than the WPF bar code.
When I was researching my purchase I downloaded from DPR a chart from a high mp camera. in my case it was the D2X but the Canon EOS 1D would do just as well. If you cut it in half in photoshop it will print over 2 A4 sheets.

Hope this link works http://www.dpreview.com/reviews/nikond2x/page27.asp

Quite good for testing your ability to hand hold a particular lens as it will show blurr in all directions. That was my origional reason for doing it. You have to remember it is only a home made job and you need to treat the results as such.

Always remember an real world picture is a far more valid test of a lens.

Don