GX85 A vs P mode shutter lag?

The camera is viewing at f/1.7.

In A mode the shooting aperture is f/1.7, so there is no aperture closing down. In P mode the shooting aperture is f/3.2 so the aperture has to close down first.

What is not commonly realized is that in some lenses, the aperture delay can be substantial (to the point of being felt by humans). Of my lenses, the most observable are 25/1.4, 20/1.7 and 45/1.8. In other words, this seems more observable in fast primes than slow zooms.

Fast primes are further complicated by situations where the viewing aperture is not wide open (typically in bright sunlight). So when shooting, it has to first open up wide for AF from the viewing aperture, then close down to the shooting aperture. Slow and noisy apertures really make them known in such situations.

For instance, the 25/1.4 typically shoots much faster in dark-ish situations, indoors and the like, than outside in the sunshine. This seems counter-intuitive until you realize it's the aperture adjustments taking time.

tt321 wrote:

The camera is viewing at f/1.7.

In A mode the shooting aperture is f/1.7, so there is no aperture closing down. In P mode the shooting aperture is f/3.2 so the aperture has to close down first.

What is not commonly realized is that in some lenses, the aperture delay can be substantial (to the point of being felt by humans). Of my lenses, the most observable are 25/1.4, 20/1.7 and 45/1.8. In other words, this seems more observable in fast primes than slow zooms.

Fast primes are further complicated by situations where the viewing aperture is not wide open (typically in bright sunlight). So when shooting, it has to first open up wide for AF from the viewing aperture, then close down to the shooting aperture. Slow and noisy apertures really make them known in such situations.

For instance, the 25/1.4 typically shoots much faster in dark-ish situations, indoors and the like, than outside in the sunshine. This seems counter-intuitive until you realize it's the aperture adjustments taking time.

This completely explains what I'm experiencing. It is most challenging in daylight. Thanks. I have never noticed this in other prime lenses I've owned.

How can I combat this in very bright situations? I don't know if it is apparent or perceived but I feel like it's causing fast moving subjects to be harder to keep still.

jagerx wrote:

How can I combat this in very bright situations? I don't know if it is apparent or perceived but I feel like it's causing fast moving subjects to be harder to keep still.

It probably does not cause fast moving subjects to be harder to be stopped as that's decided by your shutter speed. It does however insert a delay causing them to be harder to stop where you want. Hence a moving subject could end up somewhere else - not where you want or expect. This might lead to losing composition, losing focus, etc.

The key to this is to use a lens with smaller aperture delays. Probably the PRO lenses would have this as they can hardly be called PRO if you cannot catch actions because of aperture delays. However I have no personal experience. Of the lenses I have tried, the 45-175 has the smallest aperture delay and fastest AF so together they make it a very responsive lens.

alcelc wrote:

tt321 has the possible answer.

Just wish to mention:

jagerx wrote:

GX85 running firmware v1.2

G lens 20mm ASPH II f1.7

I feel like I am missing some obvious setting here, but I seem to be getting substantial lag in Program, versus no issues in Auto.

A is not Auto mode, it is Aperture priority Mode instead (i.e., shooter decides on what f/stop to use, and the camera would choose the shutter speed and ISO (if on Auto too) for a centered metering exposure. Back in the old days, together with S, they were sometimes referred to semi-automatic shooting modes.

All other settings equal/zeroed/auto. I can't figure out what's causing it. Is this just the normal speed of the mechnical shutter, with Auto defaulting to the faster electronic shutter?

Here's a vid. Please excuse my lack of coordination trying to shoot the screen.

https://youtu.be/HrJeXEb-Ugw

Thanks

Yes I forgot to edit that out just had a brain fart while typing on my phone.

I spoke to Panasonic. They say it's totally normal and the lens will suffer in very bright environments if trying to shoot a fast moving object.

alcelc wrote:

tt321 has the possible answer.

Just wish to mention:

jagerx wrote:

GX85 running firmware v1.2

G lens 20mm ASPH II f1.7

I feel like I am missing some obvious setting here, but I seem to be getting substantial lag in Program, versus no issues in Auto.

A is not Auto mode, it is Aperture priority Mode instead (i.e., shooter decides on what f/stop to use, and the camera would choose the shutter speed and ISO (if on Auto too) for a centered metering exposure. Back in the old days, together with S, they were sometimes referred to semi-automatic shooting modes.

All other settings equal/zeroed/auto. I can't figure out what's causing it. Is this just the normal speed of the mechnical shutter, with Auto defaulting to the faster electronic shutter?

Here's a vid. Please excuse my lack of coordination trying to shoot the screen.

https://youtu.be/HrJeXEb-Ugw

Thanks

I think he is trying to suggest you use "Aperture Priority" mode so the aperture does not need to change (GX85 has 1/16000th available [:grin:] ). I would also suggest this is a place for "Manual" exposure. fast action can be captured using a set aperture, shutter speed, AND focus point. Outside in full sun, start with ISO 400, f/11, 1/500th shutter, lock focus at around 10 feet. Then catch the kids anywhere near that distance and start shooting. A little practice will show you how much depth of field you have at f/11; adjust from there if you need. This is an old school method that eliminates the need for the camera to "think about" or "react to" anything. Shutter response should be as close to instantaneous as the camera can do. And the GX85 should do very well in that regard.

Street photographers use this method all the time. A wider lens will have more depth of field than the 20mm, but the 20 is not a bad starting point. It's a sharp lens, which is good. You'll be cropping in post, don't worry about it.

alcelc wrote:

jagerx wrote:

... I spoke to Panasonic. They say it's totally normal and the lens will suffer in very bright environments if trying to shoot a fast moving object.

Oop... what an explanation from Pany??

I suppose faster aperture enable faster shutter speed (not to mention a bright environment) = more capable to catch fast moving object. So should be a benefit (or must required condition) to shoot fast moving thing...

However, 20 is known on its slow focusing on C-AF (I don't own one) and I suppose what you observed might be part of the reason for it.

Panasonic cameras do not allow CAF with this lens. The option is greyed out in the menu.

Not too sure what happens with Olympus cameras.