GX7 Autofocus Hunts - in need for some advice

Duque

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Hi Everyone,

So I had the GX7 since last September and I am actually happy with it except one thing that bugs me.
There seems to be no way to keep the EVF always on, or turn it on when half pressing the shutter button to wake up the EVF when in EVF mode.

But now to my actual problem and why I am coming here.
I got the P20 the Kit mk2 and just bought me the new O25 and I realised more and more now that I have a problem in not so good light AND even in foot light with all 3 lenses (I do own the Kit and O25 only since a week)
When trying to nail focus with AFS set to smallest square in center with multi weight and A mode.
Wether its the red sofa (leather sofa with fine finish) or the red wall or the white celling. or even a foot rest that has two shades and colours. but all I get is the red framing for no focus. all lenses go back and fourth all the way the P20 does it very slow of course and then ends up with the red frame.

the Kit and O25 seem to be spot on and very fast for anything else and in good light no problem at all.

Should I change something on the settings (Metering mode, bump up max ISO which is 6400 right now).
It's not a huge problem but a bit disappointing considering the GX7s enthusiast level.

would in general speaking a ILC with PDAF solve this problem ? As i was thinking of selling the GX7 and get a E-M10 if that would help.
Is the setup with a GX7 and O25 a bad choice ?
Thank you for any possible help on this.
 

GRID

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The camera is using contrast to set the focus, and it sounds like youre trying to focus on singlecolor flat objects=low contrast?
And in low light you may need the focushelplight turned on. (if GX7 have that)
 

Duque

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Yes, focus assist light is on.

I kinda figured the low contrast with the red wall and the roof.
But the sofa has (how would you describe that in english) dimples ? like its not smooth flat surface and the foot rest has 2 different colours and shades, the small AF square covers both parts of the foot rest equally.

And the big issue I have, is that this happens on good light too.
I forgott to mention, last night I tried with the O25 to take a picture of the back cover of the kit lens where its written Olympus, AF square was over the letters. at least on the LCD you could clearly see a raise where the letters where, but still all I got was the red AF frame for no focus.

So I am wondering if the GX7 has a issue, not just with low light. And should the O25 with 1.8 be better at low light then the kit lens which is f5.3 at 25mm ?

thanks and regards
 

GFFPhoto

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My GX7 doesn't have those issues, and it's not a problem I've heard reported before. In general, the GX7 should focus as well any m43 aside from the GH4 and possibly the EM1 (the EM10 does not have PDAF).


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Duque

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So could it be a problem with the O25 ?
Is there a setting I should try out ?

- Use larger AF Square (I have it set to the smallest size)
- Use different metering mode
- Disable AF Assist light (I don't remember for what camera, but there was one where ppl recommend disabling the AF assist light for better low light AF, could have also been a Sony NEX or RX or something)
- Or something else

But good to know that the GX7 shouldn't have that problem, so it's most likely just a settings error on my side :)
 

GFFPhoto

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I don't know what the issue is. I don't think I have enough information to suggest a fix, but GRID may be correct in saying you need to put the focus box on an area with contrast for fast focusing. If I point my GX7 at a solid color wall it will have a hard time focusing, but is very quick using something like a fence with dark and light areas (and low light can be slower, especially with the P20). Try a larger square and something with good contrast. Try a corner instead of a blank wall, or the edge of a table.


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T N Args

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Post example or two please.

The smallest square is begging for trouble. It is bound to be slower than the default, the 'second smallest' square.

The smaller the square, the more the need to have an edge to focus on, in the square.

Having said that, the GX7 is excellent at AF. But like any camera, if you don't want to use it with consideration of how it works, use iA for best results. Better results come with more detailed use of settings, but not 'automatically'.
 

Duque

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Thanks for the tip on the AF Size, will try the default then.
I don't really like iA mode with the O25, the kit zoom I don't mind that much.

I am willing to learn, hence my post in this forum ^^
I will post some pictures of the AF that I think is odd that it doesn't get enough contrast from it (lens cover with olympus written on it and the foot rest).
I remember now, last night even the face of my daughter sometimes the red AF box came up, and there the smallest AF box was covering (eyes,cheek and nose) -> ok right now she is on the move like a maniac and almost never still so that makes it really hard for any AF system. but when she kept still for a few seconds even the contrast of her eyes to skin wasn't enough.

But I will for sure try the bigger AF Box, sounds like the root of my problem.
 

T N Args

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I was kind of kidding about iA, only to make my point that 'automatic' focus doesn't mean 'works equally well with all settings no matter what you do' focus. :smile:

Yes, I tried the smallest box and decided it is not for general purpose. I use the default box for single AF mode, general use.
 

Duque

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Right was home over lunch and took a snapshot of the both foot rests.
Also tried the regular size AF Box, it does work better. But not always and sometimes not at places where you would think there is enough contrast.
Below is just both foot rests, I didn't get the wall at all even with the medium AF box half wall half TV covering (red wall black TV)
Subscribe to see EXIF info for this image (if available)


The Red boxes are where I got AF error with std. AF BOX.
Green is where it worked.
These are all manually added, so they are not 100% accurate but it does cover what was covered by the AF Box.

Thanks & Regards
Alex
 

Duque

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And now that I mentioned it in my opening post.
Does anybody with a GX7 found a way to get the EVF up and running before you pull it to your eye and the eye sensor kicks in.
Covering it real quick before pulling it up doesn't work as it turns off already again.
Strange thing is. I put it to EVF mode only with the Fn4 button and the EVF stays on until the first time I pull it to my eye, then once pulling the camera away from my eye it turns off right away. With 2 options.
- if Eye Sensor is on, then every time i pull it to my eye the EVF comes on
- with Eye Sensor off, well then everything is black, the LCD the EVF...... but why doesn't the EVF stay on, or at least come on when half pressing the shutter ?!

Thanks & Regards
Alex
 

Duque

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Ok I get the flat red, but what about the clear stitching ? (is the stitching for the CDAF not contrasty enough, because it's very clear to the naked eye)
Or the foot rest next to it with a cloth top and a wood frame?

I also have this behaviour with black surfaces, would this whole AF situation work better with PDAF on a camera ? then I wouldn't jump the gun over to the E-M10 and wait for what Oly/Pana have in store for us regarding PDAF in future cameras.

Will have to search for that "law of red surfaces"

Thanks
Alex
 

T N Args

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My test results. All in low light (1/40 sec, f/1.8, ISO3200).

With standard AF box: AF works well (fast, minimal hunting) with red seam or IKEA footrest.

With small AF box: works well with footrest. Red seam no AF when seam is horizontal, but good AF when seam is vertical.

Generally no AF on plain red textile, as expected.

Conclusion: my GX7 AF is outperforming yours.
 

Duque

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Nice conclusion there, so should I send in my GX7 or is it just the way it is ?

This explains also the Red AF Box with Black and Red, because the decider was horizontal.
That is some fascinating info really, just not very encouraging to be honest.

Bottom line, it does work 95% of the time, and switching to the regular size AF box did proof to speed up things and lower the errors.
Two pics of my princess with the P20.
Subscribe to see EXIF info for this image (if available)


Subscribe to see EXIF info for this image (if available)

I don't get to do much else besides family photography, but that is more then fine by me
So thank you for your advice.
Now I need a way to wake up the EVF before I look thru it and the GX7 is all I ever wanted (ok maybe IBIS in video so I can use the O25)
 

GFFPhoto

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I also have this behaviour with black surfaces, would this whole AF situation work better with PDAF on a camera ? then I wouldn't jump the gun over to the E-M10 and wait for what Oly/Pana have in store for us regarding PDAF in future cameras.
The EM10 does not have PDAF. Only the EM1 does. An EM10 will focus pretty much the same as a GX7 (unless there is an issue with your specific camera body). If you can, take yours to a store and do a side by side comparison with another GX7, but I'm not sure there is a problem. Your results with a bigger box do not seem too unusual, and TN Argus getting better results when trying to focus on a photo of the scene might not mean much. JPEGs usually apply contrast, so the light he sees in the photo is slightly different than the light you were seeing in person. Use the standard box and try and focus on faces. You should get focus easily, fairly quickly, and every time, except for in very dim light.

At times, under challenging conditions, I will point the focus box at a high contrast area, use a half shutter press to get focus, and then recompose. I would imagine that at times, others have done the same thing.

And don't be discouraged. Every AF system has strengths and weaknesses, and overall, m43 system is quite good under most conditions. You can also switch to manual focus for static, low contrast scenes. You have a dedicated button right on the back, as well as focus peaking. I think (but I'm not certain) that focus peaking uses contrast as well, so it might be interesting to see where and how many focus peaking highlights you get when pointed at the footrest, and my guess is that might correspond with your successes in focusing.


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Now I need a way to wake up the EVF before I look thru it and the GX7 is all I ever wanted (ok maybe IBIS in video so I can use the O25)
I put a small piece of gaffer tape on the eye sensor next to the evf window. Now the evf is active as soon as I turn on the camera and stays on. I switch between the evf and the rear screen with one of the fn buttons (by default the one next to the evf but I switched the function to the wifi one. seems better locatedand I didn't like turning on the wifi by mistake).

When I hand the camera to someone else I put it on P or iauto, remove the gaffer tape and stick it on the side of the body and everything is back to "normal", which is more intuitive for most people.

About the autofocus, I've also used the face detection mode with some success. I'm thinking of storing on C1 a "party/event" mode, with face detect, medium burst, etc. I think it stars metering on the faces other than matrix though, have to make a few more tests.
 

T N Args

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..and TN Argus getting better results when trying to focus on a photo of the scene might not mean much.
Just to be clear, I did my test shots not on the image Duque posted, but on my own furniture. I happen to own the same IKEA footstool. And I also have a couple of chairs with clean red cloth upholstery with stitched seams along the base and back. This model:

Subscribe to see EXIF info for this image (if available)


I turned the lighting down to the a low level -- the GX7 meter was saying 1/40 f/1.8 ISO 3200.

Not as good as a side-by-side comparison, obviously, but I think indicative that I wasn't getting the same level of non-focusing.
 

svenkarma

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So could it be a problem with the O25 ?
Is there a setting I should try out ?

- Use larger AF Square (I have it set to the smallest size)
- Use different metering mode
- Disable AF Assist light (I don't remember for what camera, but there was one where ppl recommend disabling the AF assist light for better low light AF, could have also been a Sony NEX or RX or something)
- Or something else

But good to know that the GX7 shouldn't have that problem, so it's most likely just a settings error on my side :)
"Or something else".

Have you tried using the "focus peaking" and switching between AF and MF? Because I cover the focal lengths with a mixture of native and adapted lenses I've used this from day 1 (I use the low/blue setting, but I'm colour-blind lol), and it works very well.

By giving you a view of the strip of the image that is in focus, focus peaking is in some ways quicker to use than autofocus, somewhat counter-intuitive though that may seem.

I was staying in a Communist-era flat in far south-east Germany last week and there was a very cool old radio with all the old radio stations on the dial. With AF I could pinpoint the centre point of focus, but with focus peaking I got a better visualization of how many stations were in focus at a given aperture - which (imho) gives you much more creative flexibility in composing your image but with no loss of immediacy in terms of visual feedback.

BTW can anyone tell me which setting it is to turn the little focus square off when using a native lens in MF?
 

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