Nikon 135mm F2 DC question

[marke_gilbert]

Just wondering if anyone else has run into this--

 

I finally got around to testing my 135mm F2 DC lens.

 

When at near close focus distance, wide open, the lens appears to be focusing

about 1/2 inch in front of the focus point. Adjusting the DC ring about 1/2 way

between "O" and "Front 2" make the pint of focus much sharper.

 

Sent it to Nikon-- returned as "being within specs"-- told it was my camera.

 

Immediately mounted the lens on a different camera, exact same result. Returned

the lens again to Nikon.

 

Now, after the return, they are still claiming there is nothing wrong with the

lens.

 

Correct me if I am wrong, but shouldnt the lens be at its sharpest at the focus

point WITHOUT having to adjust the DC ring?

 

Here are sample images, obviously tripod mounted, etc...<div></div>

[marke_gilbert]

DC ring at "Front 1"<div></div>

[marke_gilbert]

sorry, those are not clear at all-- here are a couple crops<div></div>

[marke_gilbert]

and again,<div></div>

[christiaan_phleger___honol]

You're both correct in my view. Nikons' correct in that it is in spec, and you are correct in

that with your usage with this particular lens, that's the setting that gives you the

sharpness you expect. The lens as you know has the adjustable DC feature, adjusting

slightly one element which then shifts the optical formula to +/- the amount of SA. IMO

the 0 setting is not always optimum, the one I used I tended to prefer a slight correction to

the front as well, just like you found it to be sharper. Its a by-product of having an

adjustable optical system, each individual lens will require a bit of testing to dial it in. Is it

defective? No, not in my view, if it was unsharp at all settings it would be.

 

As well, its also probably due to the fact you are using digital, which seems to be sensitive

to SA. The 135DC was designed pre-digital, so lucky you that you can dial in the precise

amount of SA to match your sensor.

[christiaan_phleger___honol]

Sorry, SA in my post means Spherical Aberation.

[christiaan_phleger___honol]

Ah, you were using at close up distances. That's why Nikon made CRC, adjusts for close up.

135DC does not have CRC, just DC and RF. Most lenses lose performance close up, so

making a slight adjustment to maintain optimum performance is a small price to pay.

 

Don't forget the Zeiss 50mm FLE which has a whole separate ring to match the optical system

to the distance. You'd focus, then set the FLE ring to the distance. Forget to do the FLE ring

and your sharp Zeiss would be more than a bit soft. Great in theory but fast use in the field

was big PITA.

[marke_gilbert]

Thanks Christiaan,

 

I had considered the issue of close range correction-- but if that were the case, why does the point 1/2 inch closer to the camera appear sharp without correction applied? Shouldnt the focus point still be the sharpest, but possibly not as sharp as when adjustments are made?

[StefDevos]

Welcome to the club of unhappy DC lens owners

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00N7lY

[rudymerz]

Hi Mark,

 

I am having the same problem with my 105DC. And this goes on since over a month. The

lens was already 2 times at Nikon. And it is now worse than it was before. On Monday I will

send it in the 3rd time with my D2x. The lens shows this problem with my D80 and F100 as

well. Here is a 100% crop.

 

Rudy<div></div>

[rudymerz]

Here is the full size image.<p>

 

<a href="http://www.avianart.com/105dc/105dc-full.jpg"> 105dc-full.jpg</a><p>

[harvey_edelstein1]

I would sell it and get one of the following instead. Nikon 85mm f1.4;

Zeiss 100mm f2.0 or the Voigtlander 125mm f2.5. Nikon is AF the others are manual focus. No more out of focus shots.