Toronto Photography Meetup Group

I am (still) wrestling with the sharpness of my Nikon 70-300 VR on my D90.

One comment I hear frequently is that this lens is better on a FX format camera. Why is that?

Is a lens automatically better on a 12MP FX format D700 versus a 12MP DX format D300s? If so, why?

Isn't that counter-intuitive? Shouldn't 12MP on a larger sensor result in less "pixel" per square inch, resulting in "grainier" pictures?

What am I missing here?

Yc

well if its the same number of pixels but you are using just part of the projected image the imperfections of the glass show up more. Thats due to the higher magnification. Pixels are smaller and thus the lesn has to resolve more to meed the higher pixel density.

Advantage of bigger chip is bigger pixels and also you use a longer focal length for the same angle of view(i like this for the DOF and perspective).

I'll let someone else tackle the question of lens on a full frame vs crop sensor issue, as there is a tangible difference in the physics.

However, your last assertion isn't quite right. When pixels are packed in a lot (with a higher ppi) the net result is more noise (or grain, though don't let the film heads hear you call it grain). So in general, the higher the pixel density on a sensor, the higher the noise.

That's what makes some of the recent cameras impressive (D3s, 5Dm2, etc)... they have a fairly high pixel density but still have great low light capability with limited noise.

The lens isn't better - it doesn't collect light any differently because it's on a different body. The lens isn't a higher magnification just because a small sensor is behind it - the image circle remains exactly the same, but the part of the image circle that the sensor covers differs.

A FX body and sensor are 'better' than a DX for a number of reasons - pixel density.

What shutter speed are you shooting your zoom lens at? If you have sharpness issues then you might want to use a tripod. Pretty much guarantee that it'll be sharper (everything else being equal) if you use it on a tripod or even a monopod.

This might help:
http://www.kenrockwell.com/tech/full-fr ... antage.htm

There are reasons a lens may appear better on fullframe. Although, most of the time it's BS people use to justify the purchase of a FF camera and you see sweet FA difference in their pics.

Post some pics with exif so we can see what you're doing. And hopefully it's smarter than Mr Rockwell shooting leaves to study detail. It's not like leaves move at the slightest thought of a breeze or anything...

I will try:

Full frame lens with a crop factor sensor

Positives:

Uses the centre part of the lens which in many cases is sharper and better corrected then the outer part.

Zoom factor = crop factor x lens focal length is good for birding and such when you need the reach.


Neutral

DOF is altered rather complicated opposing parameters at work here.

Negatives

You don't use the whole lens which usually means:

Heavier weight (more glass) and need bigger filters for the same f number lens compared to a lens that is designed for the crop factor.

The crop factor represents a digital zoom as you are effectively blowing up a portion of the image, any resolution limitations and chromatic distortions of the lens are also magnified.

Wide angle lenses are now not so wide angle.

Light baffling and lens hoods are no longer optimized for the lens.

With first hand experience on this subject -- I will only say that the 70-300VRII appeared to yeild sharper results on my D700 than it did with my D90. I think pixel density had a lot to do with it. Now this being said - the 70-300VRII is a great lens for the price range, but I am much happier now with better quality glass.

I wonder if the D90 has a stronger AA filter (Anti-Alias) compared to the D700 which would yield softer images?

I had the same dilemma before with my D80 paired with my 24-70. Images are not sharp at 2.8 (I usually go to 5.6 to make them all sharp), DOF is lesser and I cannot go below 800 ISO. I usually carry my cross (tripod) during the night otherwise no picture for me.

So I started to push myself to get the D700. It is not that easy to do! I just closed my eyes and hoped for the best lol. But when I tested it, I completely forgot about my d8... d7... d9.. whatever that is called! lol. I became happier with my 24-70 and also stopping me from getting faster lenses that would satisfy my needs. DOF is just like going to heaven and back again. Sharpness at 2.8 is better with this body. Up until now I feel wounded with the price but never felt happier.

Only thing that I did notice is the distortion at 24mm which I don't see on my cropped body but I am ok with it (my family felt it was wierd and cool lol).

Thanks for all the replies.

I have been out shooting a lot this past 2 weeks and found that stopping this lens down to f8 or smaller produced much more acceptable images.

I think I will stick with this lens.

I agree with David that this is a good lens for its price.