Best aperture (sweet spot) for Panasonic 14 - 140 mm lens

Breb wrote:

I watched this yesterday, couldn't understand a word he said but found it interesting anyway. It's a pity no one else has done similar. He goes through various focal lengths at different F Nos and shows the sharpening effects. The first 14mm wide open is very poor at the edges but he stops it downs, big improvement, worth a look and be patient it's a fairly long video.

https://www.youtube.com/watch?v=0GerIcaXpeo

Thanks for the video link Breb.

Brian

Brisn5757 wrote:

alcelc wrote:

Brisn5757 wrote:

alcelc wrote:

https://www.dxomark.com/Lenses/Panasonic/Panasonic-LUMIX-G-VARIO-14-140mm-F35-56-ASPH-POWER-OIS-mounted-on-Olympus-OM-D-E-M1-Mark-II---Measurements__1136

The following were extracted from the above and combined as below in terms of the sharpness test from 14 to 140 on evert f/stop. The greener the sharper, the more red the worse.

Source: DXO Mark (Center, 1/3 field, 2/3 field, corner

I would say wide open of 14-140 f/3.5-5.6 could get the best result in most case (except for the best corner between 25~50 as from above.

In real life I keep this lens wide open all of the time. If I get any not crispy sharp result (center to 1/3~2/3 from focus point) on 1:1, 99% would be either because of shutter shock (the older models using the olde m-shutter or no e-shutter option) or stability issue of myself.

As a general rule for M43 lenses (except 45-200 and 100-300 which has their sweetest spot at f/7.1-f/8), f/8 could be the edge before diffraction will kick in to soften the output.

My 2 cents.

Thanks alcelc.

It's good when many agree on one aperture setting (f8)

Brian

Not for this lens I am afraid.

Not go beyond f/8 is just to avoid diffraction effect only.

As per DXO's result, f/8 is already not the optimal performance of this lens. Nothing wrong to shoot at f/8 ( for the better DoF because it is eq to f/16 of FF already), but if looking for the best performance of this lens (sharpest), stop down to f/8 is not.

FYI.

Hi alcelc.

If f8 is not the sharpest then I'm wondering what is, maybe going to f11 or f16 will give me better performance (sharper picture) or is going the other way having a wider aperture going to improve my sharpness (I'm not talking about DOF).

I was also told that diffraction reduces that photos sharpness so if I reduce diffraction shouldn't I get a sharper photo.

Brian

Please look at the posted graphs from DXO. The more green sections are the sharper range of the lens. The yellow are less sharp sections and red is close to poor.

From all the 4 maps showing the sharpness condition of this lens (focal length in x-axis vs f/stop in y-axis), the center, 1/3 from center, 2/3 from center and corners, throughout the zoom range f/8 started to enter the greenish yellow to yellow zone. So for sharpest result, use it from f/3.5 ~ f/5.6. F/8 is the smallest aperture that I would use if I am looking for the sharpness of this lens.

From the posted graphs, except center, @f/11 all focal length entering yellow zone... It suggest "still" reasonably sharp at center but soft elsewhere. Not ideal at all.

For quite long time I was puzzled why there were some opinions on this lens has so-so quaility. From this I could imagine this "f/8 is best idea" could be the reason. Stopping down to f/8 not only cannot produce the sharpest result that this lens, it can also make it more difficult to use when lighting condition will become non ideal!

Of course you can use it whatsoever you like.

Thank you for reading.

Here's the way to think of it:  f # is the focal length of the lens, DIVIDED by that number.

So a 25mm f/1.4 lens has a maximum opening of 25mm / 1.4, about 16mm diameter I'll guess.  at f/22, the aperture is 25mm / 22 = 1 and 1/7 mm or so.

At such tiny apertures, you're not letting in a lot of light and the light starts to behave differently as it comes through the tiny opening.   It causes diffraction.

There is some diffraction at any f stop, but at wide f stops you can't possibly see it, it doesn't affect anything.   In general f/8 is likely as high as you can go before diffraction begins to contribute to non-sharpness.  But that doesn't mean that f/11 and even f/16 are bad, if you need them go there.  Diffraction effect at f/11 is still small, for sure.

However, f/22 ...  I can't quite imagine why I would go there unless I needed to blur flowing water and I didn't have an ND filter with me.

Adrian Harris wrote:

Beautifully explained.

I agree with your evaluation, but for a two word comment on a great previous post, why could you not have trimmed so much of your quoting the previous post, to save my scrolling finger??

Great Bustard wrote:

Brisn5757 wrote:

I once believed that the smallest aperture (f22) would give me the sharpest photo as most things would be in focus but since then I've read that it varies between different lens so I was wondering if someone know what the best aperture to use for the Panasonic 14-140mm zoom lens that will give me that sharpest photo.

If not then is there some test I can do to determine the best aperture to use?

Brian

TLDR: The sharpest aperture for most situations is like from wide open to two stops down.

Let's begin with OL's MTF-50 tests of the lens:

In short, wide open to one stop down delivers the highest resolution *on the focal plane*. However, as you stop down, more and more of the scene is within the DOF. So, even when diffraction starts exacting a toll on the resolution on the focal plane, the photo, as a whole, may continue to have more resolution since more of it comes within the DOF.

However, when stopping down, one of two things necessarily happens:

• Less light is projected on the sensor for a given exposure time, resulting in a more noisy photo.
• To maintain the amount of light projected on the sensor, a longer exposure time needs to be used, which increases the risk/severity of motion blur.

So, what's the "best aperture"? Well, it's wide open if you want:

• a more shallow DOF
• less motion blur
• a less noisy photo

And all three of those come as a set. But if you want a deeper DOF for an overall sharper photo, then the "best aperture" is most narrow aperture you can use up to the point that:

• the motion blur is too great
• the photo is too noisy
• the loss of resolution due to diffraction is too great

All of these things are not merely subjective, but dependent on the scene and the viewing conditions of the photo.

I am afraid the above charts were for the older 14-140 f/4-5.8, not the 147-140 f/3.5-5.6 mk-I nor mk-II...

The one I could find for 14-140 f/3.5ish is on https://www.dxomark.com/Lenses/Panasonic/Panasonic-LUMIX-G-VARIO-14-140mm-F35-56-ASPH-POWER-OIS-mounted-on-Olympus-OM-D-E-M1-Mark-II---Measurements__1136

I set mine @ f5.6.

Guy Parsons wrote:

Brisn5757 wrote:

I once believed that the smallest aperture (f22) would give me the sharpest photo as most things would be in focus but since then I've read that it varies between different lens so I was wondering if someone know what the best aperture to use for the Panasonic 14-140mm zoom lens that will give me that sharpest photo.

If not then is there some test I can do to determine the best aperture to use?

Brian

Instead of believing others, it's so easy to do your own tests on your own lens so then you will know exactly how your sample behaves.

Choose a few different focal lengths then take shots at all apertures (1 stop apart) and later pixel peep to see which looks good/bad/acceptable.

To avoid problems due to air movements make sure your test target (whatever it is) is not further away than maybe 10metres or 30 feet away. Something with a variety of fine detail is ideal, even a newspaper page containing various sizes of font (the larger font better for the wide angle shots). In good sunlight is best as otherwise the shutter speeds may get horrible for the smaller apertures. Maybe a tripod is needed.

Make sure that you are testing the lens and not your hand-holding ability when the shutter speeds get too slow.

Be aware of course that the DOF varies so concentrate on that target as the focal point, even to the stage of making it manual focus and leaving it at the same setting for all the shots. Try and stick to the same lower ISO for all the shots.

At some aperture the detail will look best but then you need to decide if that aperture delivers enough DOF for the occasion.

As an aside using my Oly 12-40/2.8 it really works out that wide open to f/4 is best at various focal lengths but I have settled on a MySet that defaults to f/5.6 as the best general aperture that delivers image quality and sufficient DOF for my usual out and about and travel shots. I rarely change from that for most shooting. Maybe as far as f/8 or f/11 for a closeup to get better DOF at the expense of some image quality.

As for f/22, I would never go there with any M4/3 lens, you simply lose too much quality.

My story about that is buying a Samyang 7.5mm fisheye, straight out the box and onto the camera and took a shot of the neighbour's house, yuk, what have I bought? The image was awful. Oh duh, looked at the aperture ring and it was set to f/22, opened it up to f/4 and suddenly it was a good lens. A huge difference.

Hi Guy.

I get tried of running a lot of tests on my camera and lens so I was hoping that someone has tested this lens (you often get tests in photograph magazines, YouTube, etc)  so I could get the results. But I may do a few quick tests as lens sometimes vary a bit.

So far F8 and maybe a bit wider seems to be the sweet spot.

Brian

JosephScha wrote:

Here's the way to think of it: f # is the focal length of the lens, DIVIDED by that number.

So a 25mm f/1.4 lens has a maximum opening of 25mm / 1.4, about 16mm diameter I'll guess. at f/22, the aperture is 25mm / 22 = 1 and 1/7 mm or so.

At such tiny apertures, you're not letting in a lot of light and the light starts to behave differently as it comes through the tiny opening. It causes diffraction.

There is some diffraction at any f stop, but at wide f stops you can't possibly see it, it doesn't affect anything. In general f/8 is likely as high as you can go before diffraction begins to contribute to non-sharpness. But that doesn't mean that f/11 and even f/16 are bad, if you need them go there. Diffraction effect at f/11 is still small, for sure.

However, f/22 ... I can't quite imagine why I would go there unless I needed to blur flowing water and I didn't have an ND filter with me.

Thanks for the info JosephScha.

Photographing flowing water in low light conditions might be better than using f22.

Brian

nevada5 wrote:

Here's one review (test) of the f/3.5-5.6 lens

https://www.ephotozine.com/article/panasonic-lumix-g-vario-14-140mm-f-3-5-5-6-lens-review-22632

Thanks for the useful information in that link nevada5.

Brian