Panasonic 14-140 sweet spot.

Have any 14-140 users identified a sweet spot for using the lens at or near to the long end.  I use my 14-140 as my city walkabout lens with the occasional landscape and I'm not very self critical when it comes to that part of my photography so just about anything between 3.5 and 11 works for me.

But I'm now using it to try to shoot 4K butterflies in flight and I need very fast shutter speeds so I need to get the optimum settings.  I've discovered that 1/3200 is a good speed and anything less than 1/2000 is not great.  I'm pushing the ISO to 1600 but not too happy beyond that and to achieve that for the other part of the triangle I need to be as wide open as possible.  At full zoom maximum aperture is f5.6 would anybody like to comment on whether they think it's OK at F5.6 or do I need to stop down a bit to 6.3 or 7.1.

Trevor Carpenter wrote:

...... At full zoom maximum aperture is f5.6 would anybody like to comment on whether they think it's OK at F5.6 or do I need to stop down a bit to 6.3 or 7.1.

I've seen some of your butterfly shots and from the looks of it you're doing pretty well with the apertures you are using.  Going to 5.6 may give you a little more speed but would also slightly reduce field of view which may make cost you an in focus image.  Best thing to do seeing as you have the lens is try it and see for yourself.

eyespy wrote:

Trevor Carpenter wrote:

...... At full zoom maximum aperture is f5.6 would anybody like to comment on whether they think it's OK at F5.6 or do I need to stop down a bit to 6.3 or 7.1.

I've seen some of your butterfly shots and from the looks of it you're doing pretty well with the apertures you are using. Going to 5.6 may give you a little more speed but would also slightly reduce field of view which may make cost you an in focus image. Best thing to do seeing as you have the lens is try it and see for yourself.

I have tried it but because there are so many factors that come into play I'm finding it difficult to understand whether any issues are aperture, DOF, High ISO too slow shutter speed, user shake etc etc,  We have almost total agreement on this forum that the 100-300 has a sweet spot of F7.1 but I don't recall anybody ever mentioning a similar fact for the 14-140.

Might this be of your interest?

According to the MTF table (unfortunately tested on G3!), it seems that generally f/8 might be the most safe play. @14MM, best at f/8 (from f/5.6 to f/11); @50mm, best at f/5.6 (from f/4.9 to f/8), @140mm, best at f/11 (from f/5.6 to f/11).

alcelc wrote:

Might this be of your interest?

According to the MTF table (unfortunately tested on G3!), it seems that generally f/8 might be the most safe play. @14MM, best at f/8 (from f/5.6 to f/11); @50mm, best at f/5.6 (from f/4.9 to f/8), @140mm, best at f/11 (from f/5.6 to f/11).

Thanks.  I think it will be a struggle/impossible for me to get to F11 at 1/3200 sec which is what I was fearing

Frasier Krane wrote:

Trevor Carpenter wrote:

alcelc wrote:

Might this be of your interest?

According to the MTF table (unfortunately tested on G3!), it seems that generally f/8 might be the most safe play. @14MM, best at f/8 (from f/5.6 to f/11); @50mm, best at f/5.6 (from f/4.9 to f/8), @140mm, best at f/11 (from f/5.6 to f/11).

Thanks. I think it will be a struggle/impossible for me to get to F11 at 1/3200 sec which is what I was fearing

First and foremost, let me say that the answer to what F-number is best for ANY MFT lens is NEVER, EVER F/11. It has never happened, and it never will. By that point, diffraction has kicked in and substantially reduced IQ.

Second, look at the actual charts on ephotozine.com. There is no significant difference on those charts between f/5.6, f/8, and f/11. When that's the case, wide open is your best bet. This is because diffraction may be causing deleterious effects that the ephotozine.com methodology may not be picking up on.

This brings us to dxomark.com.

http://www.dxomark.com/Lenses/Panasonic/Panasonic-LUMIX-G-VARIO-14-140mm-F35-56-ASPH-POWER-OIS-mounted-on-Olympus-OM-D-E-M5---Measurements__793

If you look at the acutance profiles, the center sharpness is best at 140mm at f/5.6. It's slightly better at f/5.6 than it is at f/8. But the edge and corner performance is overall best at f/8.

So, if you can keep the target more or less in the center of the frame, then there's no practical advantage to stopping down from f/5.6. If the subject could be anywhere in the frame, then f/8 might perform better, but, honestly, f/6.3 or f/7.1 might be all you need to get the edges as good as they'll get.

But, again, with telephoto lenses, I tend to look almost solely at the center performance because I generally don't use these for landscapes but to isolate individual subjects. So, I would stick to wide open with this lens.

Thanks for the explanation

Thank you Frasier, and thank you Trevor for starting the thread.

As was mentioned most think that the sweet spot fo the P100-300 is f/7.1, which is what I came to  use when shooting it with my GX7. Now that I have the E-M5 II, I find f/6.3 at 300mm is very acceptable. My wife recently purchased a P14-140 for her E-M5 II, and she thanks you both for the insights on this lens....she'll see how f/6.3 works at 140mm.

Can't say I noticed a sweet or a sour spot with my 14-140 MK II.

That said I was only taking baby steps in use of A and S modes when I had this lens.