Nikon 70-300VRII -- Sweet Spot

I know, this is a wide open question, but I am going to ask anyway. Ha!

In another thread on diffraction, etc I watched the video and then ventured off into the CP-L video by the same guy and I began to wonder about the 70-300mm VRII 4.5-5.6. Of those of you who own or have used the lens, what have you determined to be the "sweet spot" f-stop for sharpness at 300mm. In other words, the smallest aperture setting that you start to lose sharpness.

Thanks

After watching the video again, I see that I missed the camera used will make a big difference on the "sweet spot", so I guess that there really isn't a good answer for my question, except..................................Get out and play to determine it for yourself. Ha!

I don't really pay too much attention to it, but...

Isn't the general rule two-stops down from wide open on just about any lens?
.....

Set up a flat target subject of some sort with some fine detail at 5 feet. Get the focus zeroed in on it and shoot a series stopping down with each shot. Better if you can use flash for the lighting, to eliminate any camera shake blur.

Actually, I'm thinking you won't notice much softness form just stopping down at 300mm.

I shoot mine wherever I have to to get the shot I need. For my BIF shots I shoot manual and about F8 or so.

Isn't it recommended to get the absolute best out of this lens - to zoom back in a bit even at 250mm isn't the center IQ supposed to be very very good even comparable to some of nikons primes? i have checked this on a few comparison sites where you can change lens settings and check on a chart, i have even done this with large amounts of page zoom to really show the difference - from 300mm even at f8 compared to 200mm even wide open the difference in clarity and IQ is quite amazing - almost a different lens, so i assume it should be not much different at 250mm(perhaps marginally softer) but shouldn't be much - or i might be wrong?

P.

Thanks all for your interesting comments. [MENTION=13090]Horoscope Fish[/MENTION], Yes that is the rule of thumb/starting point...2 stops closed from wide open. I really hadn't paid much attention to it either until I watched the video posted on Diffraction. To be honest, I usually shot fairly tightly closed down, thinking I wanted to get a long DOF. I opened up usually only to get the exposure with the shutter speed I wanted. I then started using Manual with auto ISO. That works pretty well for BIF, but again, I had the aperture set probably a little tighter than needed. I have been using f11 or tighter and about 800-1000 shutter for my BIF shots on my walking around opportunity derived shots. The video pointed out some interesting things to play with. I need all of the help I can get with these old eyes and slower moving, shaky body. Ha! In the Backcountry video, they demonstrated some landscape shots and how fStops changed things. Not big changes, but enough for me to play. Ha!

Here's what i do with mine -
1) zoom back a bit 250mm instead of 300mm - should help IQ quite a bit and help focusing a bit?
2) use f7.1 as it is still stopped down a bit.

I have stuck a little sticky round label on mine at the 250mm mark for easy quick selection.

P.

Post #2 was the best answer.

Generally speaking the best part of any lens is the middle ground, but everything changes everything else.

While a lens may be sharpest at f/8 or f/11 and mid-zoom, 300mm at f/32 may beat the socks off 200 or 250 at f/11 if you have to crop and enlarge to get the final image. And a sockless lens could get damaged in transit.

Its amazing and good news for us 70-300vr owners - Digital Picture show the 70-300Vr having the same level of clarity and IQ at the center as long as you zoom back to 200mm, as the nikon 300mm f2.8 AF-S lens, this level of IQ is consistent from f5.6 to f8.

So it just goes to show how good our lens is if you zoom back a bit.

I assume 250mm will be similar?

P.