My super-zoom AF Fine-tune dilemma

[BruceLeventhal]

I really wanted to title this thread "my AF Fine tune Hell," as I am stuck between a rock and a hard place.
With the advent of high resolution sensors, the flaws in optical design definitely rears its ugly head...

My primary wildlife lens is a 200-400mm f/4 VR1. As many know, this lens is quite stellar within 15-20meters, but begins to suffer as the subject is shot from a distance. In the case of my lens, it is a solid performer throughout its range... sort of... In general, I can rely on AFC w/ various af-point distributions to produce sharp images on my D500 w/ no AF Fine-tune correction. I typically stop the lens down to f/4.5 at 400mm as this 1/3 stop improves image contrast when compared to when the lens is shot wide open.

When using the lens for compressed landscapes, I tend to rely on liveview AF, and when I use liveview, the images do not suffer from the infamous loss of quality at a distance...

However, if I rely on the camera's AF system (sans liveview), my photographs are soft. This tipped me off to a flaw in my lens... the AF system seems to be optimized for one focusing distance but not another. In fact, if I set my AF fine tune to -10, then the lens produces great images when pursuing distant subjects.

Herein lies my dilemma and envy of the Sigma dock system. I want to fine tune my lens for different focal lengths and distances!

I am curious if others have experienced similar issues with their lenses. How have you dealt with this dichotomous performance? My current solution is as follows: Set the function button to automatically pull up the first selection in "My Menu." This brings me to the AF fine-tune menu. When shooting birds in flight or distant wildlife I turn AF fine tune on (set to -10), when shooting nearby subjects, I turn it off.

To be honest, I do not want to deal with this... I am now considering the sale of my otherwise stellar lens, with the possibility of replacing it with the 150-600mm Sigma Sport or 120-300mm f/2.8 sport + 1.4x.

I am open to other ideas as well.
cheers,
bruce

[the solitaire]

The Sigma 120-300 should not be a bad choice.

A problem I encountered with AF fine tune is that lenses do need a different tune at different operating temperatures. The bigger and more exotic the glass elements become, the bigger this difference becomes as well.

With my 85mm f1,4 AF-D I need to gauge and set AF fine tune every time I shoot the lens. The thin DoF doesn't allow any sloppyness in that regard at all. Even on a D3

My generl solution is to focus manually. That way I'm saved of this pesky AF finetuning

[John Geerts]

With my 85mm f1,4 AF-D I need to gauge and set AF fine tune every time I shoot the lens. The thin DoF doesn't allow any sloppyness in that regard at all. Even on a D3

My generl solution is to focus manually. That way I'm saved of this pesky AF finetuning

Yes, with 'fast' lenses thé approach.

[BruceLeventhal]

Yes, with 'fast' lenses thé approach.

Thanks for your thoughts John and Solitaire,
In the 90's I would not have doubted the advantages of manual focus during an era when AF was in its infancy. In fact, I was just fine with my FM's and FE's. Wildlife photography was all about being there and "acceptable sharpness" with lenses like the amazingly innovative 400mm f/3.5 edif, however... these eyes are 52 years old and were it not for the high refractive lenses in my glasses, correcting my vision would require lenses as thick as coke bottles  , thus... manual focusing birds in flight and fleeting moments with swimming aquatic mammals is just out of the picture for me!

I have had great success with my 200-400mm lens, so it is not about the overall sharpness of the lens (see attached). For me, it is the inconsistency when it comes to distant subjects.
At this point, I am seriously considering the 120-300 f/2.8 because of its overall quality, similar niche to my current lens, and its dock that allows for critical fine tuning.
...note the first image was shot this morning.
regards,
bruce

[longzoom]

To check your combo you may do this thing: set your combo on the tripod, set the lens to the long end, using LV try focus it on the very good bright target. Check with loupe position on the distance scale - make sure it is clearly visible.   Check the file on your monitor - must be Swiss precise, if mistake, repeat focusing. Then, set the combo to regular AF, use central AF sensor. By implementing +/- FT units, one-by-one, set the distance scale on the lens to the same - SAME - position, check with loupe, again.  Check the file - MUST be the same, as it was with LV. If not the same, with repeating try (say, 8 out of 10 is success!) - body needs adjustment. If the same at the long end, but significantly FT +/- differentiation thru the zoom - the lens needs serious FT adjustment  thru pro attention. Do not get confused with some +/- deviation of the distance scale thru the zoom - its perfectly normal, but FT must NOT migrate MUCH. It must stay inside the field of DOF. This operation is working better on high quality pro lenses - 200-400, 80-400, 70-200, so on.  Huge amateurish lenses could be check at their long end, as well as prosumer ones, such as 28-300.  Good luck!  LZ   PS.  Beautiful images!