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One other thought before you send your lens off. All the images you posted look to be a stop or so under exposed. The whites on the test charts aren't really white. Underexposure robs contrast and edge contrast is basically what we perceive as sharpness. You might try reshooting some of these images with the target well lit and using positive exposure compensation as needed to keep the bright whites white (without clipping the whites of course).I called Nikon in NY and they said after 2011 they stopped servicing that lens because parts are no longer available. I'll call APS Nikon in Morton Grove to see if they can check/adjust alignment since they serviced it 11/2020.
Unfortunately an 8 second exposure is not useful for testing a 600mm lens. A car driving by your house will shake it. You walking around in your basement will shake it. These are not definitive tests.Hey all, shot with my lens, attached is a full frame image at f/4 and 100% crops at the center, left edge and right edge. The camera was a D850, ISO 40. Test distance was the length of my basement of 29'. Unfortunately, the USAF charts are at least 50 yrs old and no longer pristine white. Adjusting the resolution #s for that distance, central resolution was 90 lp/mm ( just shy of group 2, pair 5) and the left or right edge was 75 lp/mm ( just shy of group 2, pair 4). Based in the acutance of these images, do you feel the lens is worth shipping to APS (Morton Grove, Il) for evaluation/adjustment? Nikon in NY won't touch it as they say parts are no longer available. If you feel service would be beneficial and APS declines, any suggestions on an independent service shop that could work on a lens this size? Any help would be appreciated. Thanks.
I don't believe this is a good method for testing lenses.There was no shake in the test. The shutter was opened for 10 seconds in the dark and exposure was made by turning the light switch on and off for a few seconds. This eliminated any chance of vibration from mirror slap or shutter vibration.
Ah. I didn't catch that. This is a very old lens.This was a AFS Mk II version so there is no VR.
Yes it is a nuisance but well worth the trouble. Even for 3rd party lens issues. I sent my d7200 and my Sigma 150-500 to sigma because after they replaced the focus motor board it wasn't as sharp as before. When I received them back it was sharper than ever. I was honestly impressed. Both those pieces are long gone but a good lesson learned.I agree - unless there is something in your technique that is allowing vibration to cause the softness. That lens should be much sharper.
Working with Nikon for service, be sure you send them your test images including the LensAlign samples. Let them see that it's not sharp so they don't think it's a calibration issue. You might send your camera body as well. I know it's a nuisance, but it gives them everything needed to assess.
I'm assuming you have your gear insured. Check to verify, but most policies cover losses if gear is being shipped. There is no need to buy extra insurance for your gear to be shipped - and on that lens it could save you $100.
I have to agree with Steve. Your lens appears sharper in the corners than the center by far in your previous post of crops. The one where you show center and right and left corners. The center should be as sharp if not sharper than the corners as I understand it.Lastly I'll post images of center crops for the 600/4D AFS Mk II at f/4 & f/5.6 as well as my 500/5.6E PF at f/5.6 for comparison (which probably performs close to the current 600/4E FL). While resolution is similar for all three, the 500/5.6E @ f/5.6 has a bit more bite in contrast than the 600 at f/4 but stopped down to f/5.6 the 600 comes very close to the 500/5.6. The main question I have is should the 600/4D AFS II have more contrast wide open than my sample? Stopped down a little it's pretty good.
600 @ f/4
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600 @ f/5.6
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500 @ f/5.6
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That's probably a good decision. As you say, it gets better as you stop down, but just doesn't seem to keep up with today's tech.Based on comments, especially from Steve Perry, I've decided to return the lens to the seller. Resolution of the lens is quite good even at f/4 but contrast is sub-par wide open by today's standards for high MP digital cameras. Given that it's contrast improves significantly by stopping down just one stop with f/8 as optimal, I suspect it performs close to expected since the optical design dates back to the mid-1990's when film was their main format. Also it's interesting to note that according to FoCal's database on IQ, the typical 600/4 AFS II performance wide open scored 63/100 while the G and FL version scored 80/100 and 89/100 respectively. This seems about consistent with my lens.
I still have an old 4/300, the screwdriver version. On modern digital bodies the contrast isn't very good wide open, presumably because the coatings aren't really up to scratch compared to modern coatings. Still like that old lens, however, must be one of the toughest lenses I own.Resolution of the lens is quite good even at f/4 but contrast is sub-par wide open by today's standards for high MP digital cameras. Given that it's contrast improves significantly by stopping down just one stop with f/8 as optimal, I suspect it performs close to expected since the optical design dates back to the mid-1990's when film was their main format.
I've used Nikon APS in Morton Grove with decent results, but I had a 80-400 VR 2 repaired by them for impact damage at a cost of about $500. I calibrated the repaired lens with Reikan Focal and astigmatism was off the chart and focus quality was not good. I then sent the lens to Nikon in New York and retesting showed markedly improved results. From this experience, I agree with Steve that it would be a good idea to send the lens to Nikon.Hi Steve, I bought it from a seller on FM who provided documentation from Nikon APS (Morton Grove, IL) that shows the lens had a complete service 11/2020 including motor replacement, element cleaning, bayonet mount replacement and general CLA. Do you suggest sending it back to them or Nikon in NY? If so what should I ask them to do?