Nikon 24mm F2.8 AFD distortion

[leif_goodwin8]

<P>I have a Nikon 24mm F2.8 AFD lens that I primarily use for close

up work. I like to photograph fungi and like the idea of getting the

background into the scene. I prefer the 24mm lens to my Nikon 28mm

F2.8 AFD lens as it is much sharper, focusses closer and the 28mm is

plagued by severe chromatic aberration. However when taking close up

pictures I see huge amounts of rectilinear distortion that pretty

much ruins any photo. Is this a feature of a 24mm lens or is it a

feature of this particular lens?</P>

 

<P>Here is an example:</P>

 

<A

HREF="http://mysite.freeserve.com/ukfungi/CantharellusCibarius.html">C

hanterelles</A>

 

<P>You'll notice that the ground appears to drop downwards either

side of the Chanterelles. </P>

 

<P>Here is another example:</P>

 

<A

HREF="http://mysite.freeserve.com/ukfungi/GrifolaFrondosa2.html">Grifo

la frondosa</A>

 

<P>Notice how the side of the ditch on which the tree and fungus grow

appears curved.</P>

 

<P>I don't see this distortion with the 28mm lens.</P>

[mark_scheuern]

It looks like converging lines caused by perspective rather than rectilinear distortion. It's what happens when you map three dimensions into two. Shoot a grid of lines with the camera perfectly perpendicular to the plane the lines lie in and I bet you'll see very little barrel or pincusion distortion.

[frank uhlig]

Simple answer: wide angle optics do that; simply borrow someone's 20 mm and see the same effect more pronounced.

 

I think/feel that over around 35 mm focal length, this effect becomes somewhat invisible, certainly by 50mm and above. Then the tigthening up of perspective with tele lenses sets in.

 

So, try a longer lens. Incidentally, it does not matter whether you use a Zeiss 24mm, a Canon, Minolta, ... they all cannot step away from the physics of the world, can they.

[leif_goodwin8]

Thanks. I was afraid it was a geometric effect.

[lachaine]

I have that exact same lens. I've used it for some architectural shots. What I find is that it has virtually no linear distortion (ie. pincushion or barrel, and I really mean virtually none). What happens with the 24mm focal length though is perspective distortion towards the egdes - perfectly normal and expected the closer you get to the super wide angles. This means that objects that are, say, close to the edge of view, nearer the camera and near the bottom of the picture will flare outwards - but if they are straight lines, they remain straight lines anyway, even though they converge downwards. Hard to explain but easy to see. A 28mm lens will show this much less. But as you move closer to the super wide angles, this happens, and the 24mm is close enough to start seeing that effect. You can see what I mean in this uncropped photograph taken with the lens.<div></div>

[Jerry_]

Any chance you can borrow a AF 60mm f2.8 (D or non-D) Micro-Nikkor lens?

The close-up results may be better suited for your work.

[david_h._hartman]

Consider a 28/2.8 AIS. Dont substitute an AI as the AI

and AF versions are apparently similar and kind of puppies if you

will. These versions lack CRC (close range correction). The 28/2.8

AIS is good but ordinary at distance. I have not owned a 28mm

lens since about 1971 and just Friday took delivery of a 28/2.0

AIS. Im going primarily on Bjørn Rørsletts reviews.

You might also consider the 28/2.0. The 28/2.8 AIS focuses to 0.2m

and the 28/2.0 AIS to 0.25m.<br>

<br>

Here is a clip from Bjørns 28/2.8 AIS subjective

evaluation...<br>

<br>

<em>"Nikon designed this lens [28/2.8 AIS] to yield sharp images

even used for close-up photography. This was achieved thanks to

its advanced 8-element design and a CRC feature acting on the

front elements as with the 28/2 Nikkor. Images taken up close

really are extremely sharp in the middle part of the picture and

sharpness extends quite gracefully into the corners"</em><br>

<br>

You can find his subjective evaluations here...<br>

<br>

<a href="http://www.naturfotograf.com/lens_surv.html"

target="_new"><u>Lens Survey And Subjective Evaluations</u></a><br>

<br>

<a href="http://www.naturfotograf.com/" target="_new"><u>Nærfoto

Bjørn Rørslett site entrance</u></a><br>

<br>

You will want to check out his whole site carefully as he is a

professional nature photographer and macro specialist.<br>

<br>

All the best,

[lachaine]

I actually like your photos as they are, but to add to what I already posted above, I don't think you can do what you want to do with the 24mm without the kind of distortion you see. It can focus very close, but it's for the super wide angle effect of foreground against background, not to produce close-ups.

[leif_goodwin8]

Pierre: Thanks for the nice example to confirm the geometric effect.

 

Gerald: I own 60mm F2.8 AF, 105mm F2.8 AFD and 200mm F4 AIS micro lenses. You might guess that I am a bit of a close up nut. I like to experiment and really like wide angles close up.

 

David H: I own 28mm F2.8 AFD and 28mm F2.8 AIS lenses. I bought the latter on the recommendation of Rorslett and others. The AFD version is so so, and sometimes shows quite serious chromatic aberration. I keep meaning to sell it. It can do an okay job though:

 

http://mysite.freeserve.com/ukfungi/CortinariusTorvus.html

 

I'll stick to the 28mm AIS lens in future for wide angle close ups.