No that's not the same thing. The best optics of any lens will always be the center. So whether it's FX or DX really doesn't matter although it is falsely assumed that any DX lens will be better because of the cropped image.

Sweet spot is actually what PB PM said above. Usually, depending on the lens,it's between f5.6 or f9. Focal length of a zoom lens also plays into the sweet spot.

Look at the interactive graphic from dpreview for the old 70-200mm VRI. Move the focal length and aperture scales left or right and watch the colors change. Blue represents the best image quality possible. So for a DX camera the sweet spot for that lens is f4 or f5.6 at 105mm.

http://www.dpreview.com/lensreviews/nikon_70-200_2p8_vr_n15/page4.asp

I thought the "sweet spot" also described the use of an FX lens on a DX camera, where the cropped image avoids edge softness and corner vignetting.

That is not really true. Most DX and consumer lenses, for example have a sweet spot between F5.6 and F9, with F8 generally being best.

For Pro grade lenses, some of which are sharp wide open, they are often very good across the entire range.

I was told - a very long time ago - that the "sweet spot" on any lens was a 1 fstop above its maximum aperture. (e.g., f/4 on an f/2.8 lens, etc...)

And it has a beautiful viewfinder:
http://nikonrumors.com/forum/topic.php?id=526

The lenses were OK, but I was referring to the gorgeous handling of the OM1/2. They became an extention of my body in a way that todays complex cameras never can (for me anyway). My favourite was the bomb-proof all mechanical OM1.

But are the results the same?

spraynpray said:
I had the OM1, OM2 and a lot of system lenses and accessories. If only you could 'convert' them to digital eh? Life was simple then!

You could actually, lenses at least, Olympus makes an adapter for OM lenses for E series and PEN too.

I had the OM1, OM2 and a lot of system lenses and accessories. If only you could 'convert' them to digital eh? Life was simple then!

I still have my OM-2, which does the off the film metering, too—one of the best ideas anyone had.

Yup That OM 10 was a gem.. Had one. Great for taking Lightning! That off the film metering was/is just amazing.. I don't think we have an equivalent system still!

like someone once said, just dial f8 on Your camera, get a nice spot and You will get a great picture. but generally each lens performs best around f8.

Thanks guys.

I am trying to keep a cap on expenditure now I am retired as I can't afford too many lenses, hence the panorama use of the 18-105. That is also why I don't have an FX camera or even a D90 (although I regret that a little due to the lack of second control ring on the D5000). My old OM10 was a peach to handle >sigh<!

That is a useful site! It is good to see easily the variation in distortions with focal length and aperture which is what I asked about. One for the favourites indeed.

generally "sweet spot" refers to aperture, less commonly to focal length.

Stop down to f/8-f10 to get the best image quality.

and as jonny said, check photozone for the focal length with the least amount of distortion

Short (probably unhelpful) answer is that the 18-105 isn't the best lens for panoramas. But if it's the only option, then 24mm is a pretty good place to live on that particular lens. Hover your pointer over the different focal lengths in the distortions section on this page to see what I'm talking about: http://www.photozone.de/nikon--nikkor-aps-c-lens-tests/410-nikkor_18105_3556vr?start=1

Hi chaps,

Newbie question: I have a D5000 with 18-105mm and 100-300mm lenses. I have just read that lenses have a 'sweet spot' where they give the best results, so I have two questions:

1/ Does anybody have any idea where the sweet spots are for those lenses, and

2/ When I use the 18-105 for lanscape panoramas, should I just automatically bring it back to 18mm or use it at, say, 35 or 50mm to reduce distortions?

So many questions, so little time.....

TIA.