NRothschild
Veteran Member
Hi Tony,
I agree with your comments above, although I may come to different conclusions. By adding that RRS two point suspension, I agree that you are simply moving the main single pivot point from the lens to the ball stem. (Or maybe removing one of many pivot points, depending on how you want to look at it). Now, which is more stable, the lens foot or the ball stem? Although purely speculative, I suspect that a good ball stem is more stable than the lens foot and collar. The modern collars and lens feet tend to be very wimpy, presumably to reduce weight (and cost).
While there is no perfect solution short of two tripods, which is not practical except shooting maybe landscapes, the problem I see with long lenses is not so much that there is some vibration, but that there is so much vibration.
Here I did a test of the 300 F/4 AFS stock foot verses the Kirk two point suspension collar.
http://www.pbase.com/nrothschild/kirk_300_f4_collar
The "Self Timer" tests are the acid test of stability because that test relies solely on the rigidity of the support system. I view that as the reference image.
Now look at my two images using LLT with each foot. Note that at higher shutter speeds (1/15s and 1/50s) I was able to get reasonably sharp images with LLT with either foot. But, at 1/5s I was unable to get a sharp image using LLT with the stock foot, but I was able to get a good image with the Kirk foot.
From that I conclude that, for any given support configuration, LLT results in less consistency as shutter speed declines. If you then make the support more rigid, you can go to progressively slower shutter speeds with reasonable consistency.
Applying that test and general conclusion to the matter at hand, the RRS two point suspension setup, I would think that the RRS setup would provide more consistent results with LLT and at lower shutter speeds.
The question is: is the improvement worth $500?
The 300 F/4 is not a particularly difficult lens to shoot, even with the stock foot, because it is rather puny compared to the bigger guns. My extensive experience with a 500 F/4P and my brief usage of a 400 2.8 told me that that lens is HIGHLY unstable and that is why I would think that the RRS device should at least help, although to what degree would need to be tested.
This is speculation, of course, and I don't believe anyone could come to any more firm conclusions without actually testing that device. The good news is that you have a return privilege and therefore the opportunity to test the actual utility of that device.
Interestingly, I have seen some test images shot with a 200-400VR on a 1325 and 1548. Those tests actually showed the 1325 to be more stable in that particular configuration. I think the guy knew what he was doing and he certainly recognized that his results were counter-intuitive. He believed that the resonant frequency of the 1325 may have just been different enough to make his configuration happier than on a 1548. That just goes to show that it is difficult to make generalizations and I am not saying the same would be true with a 400 2.8, which is a very different lens class.
Although I had to pay about $27 for the report that contained those test images, I thought it was money well spent considering the huge sums we throw into our support systems and the scarcity of good test data. It gave me some good ideas for my own testing.
http://www.diglloyd.com/diglloyd/infos/TheSharpestImage/TheSharpestImage-info.html
--
Regards,
Neil
I agree with your comments above, although I may come to different conclusions. By adding that RRS two point suspension, I agree that you are simply moving the main single pivot point from the lens to the ball stem. (Or maybe removing one of many pivot points, depending on how you want to look at it). Now, which is more stable, the lens foot or the ball stem? Although purely speculative, I suspect that a good ball stem is more stable than the lens foot and collar. The modern collars and lens feet tend to be very wimpy, presumably to reduce weight (and cost).
While there is no perfect solution short of two tripods, which is not practical except shooting maybe landscapes, the problem I see with long lenses is not so much that there is some vibration, but that there is so much vibration.
Here I did a test of the 300 F/4 AFS stock foot verses the Kirk two point suspension collar.
http://www.pbase.com/nrothschild/kirk_300_f4_collar
The "Self Timer" tests are the acid test of stability because that test relies solely on the rigidity of the support system. I view that as the reference image.
Now look at my two images using LLT with each foot. Note that at higher shutter speeds (1/15s and 1/50s) I was able to get reasonably sharp images with LLT with either foot. But, at 1/5s I was unable to get a sharp image using LLT with the stock foot, but I was able to get a good image with the Kirk foot.
From that I conclude that, for any given support configuration, LLT results in less consistency as shutter speed declines. If you then make the support more rigid, you can go to progressively slower shutter speeds with reasonable consistency.
Applying that test and general conclusion to the matter at hand, the RRS two point suspension setup, I would think that the RRS setup would provide more consistent results with LLT and at lower shutter speeds.
The question is: is the improvement worth $500?
The 300 F/4 is not a particularly difficult lens to shoot, even with the stock foot, because it is rather puny compared to the bigger guns. My extensive experience with a 500 F/4P and my brief usage of a 400 2.8 told me that that lens is HIGHLY unstable and that is why I would think that the RRS device should at least help, although to what degree would need to be tested.
This is speculation, of course, and I don't believe anyone could come to any more firm conclusions without actually testing that device. The good news is that you have a return privilege and therefore the opportunity to test the actual utility of that device.
Interestingly, I have seen some test images shot with a 200-400VR on a 1325 and 1548. Those tests actually showed the 1325 to be more stable in that particular configuration. I think the guy knew what he was doing and he certainly recognized that his results were counter-intuitive. He believed that the resonant frequency of the 1325 may have just been different enough to make his configuration happier than on a 1548. That just goes to show that it is difficult to make generalizations and I am not saying the same would be true with a 400 2.8, which is a very different lens class.
Although I had to pay about $27 for the report that contained those test images, I thought it was money well spent considering the huge sums we throw into our support systems and the scarcity of good test data. It gave me some good ideas for my own testing.
http://www.diglloyd.com/diglloyd/infos/TheSharpestImage/TheSharpestImage-info.html
--
Regards,
Neil
