GH4 Lumix 14-140 f4/5.6 looks blurry!

B

blando3

Well-known member
Okay, so I've been shooting live speaker presentations on the GH4 using my Lumix 14-140 4/5.6. Available light, ISO 640, f6.3. The shots are coming out somewhat soft, even after zooming in for focus, like always.
Is this just the nature of this lens in low light? I've had some beautiful results with it outdoors.

Should I get something else, even I compromise on focal length? Maybe a Lumix 12-35 f2.8 or Olympus 12-40 f2.8?
Thanks!
 
When you say 'zooming in for focus', do you mean you are physically rotating the barrel to zoom the lens, or are you using the digital focus check function?

If it's rotating the barrel to zoom the lens, this is probably where the problem is, since these lenses are rarely parfocal (keeping the same focal point when zooming). If you set focus at 140mm, then zoom back out, you will probably get soft images.

Instead, set your focal length for the shot, then use the camera's digital focus check punch-in function to set focus. That way you will have sharp images at the focal length you desire.

Hope this helps!

Cheers,

Paul :)
 
visceralpsyche said:
When you say 'zooming in for focus', do you mean you are physically rotating the barrel to zoom the lens, or are you using the digital focus check function?

If it's rotating the barrel to zoom the lens, this is probably where the problem is, since these lenses are rarely parfocal (keeping the same focal point when zooming). If you set focus at 140mm, then zoom back out, you will probably get soft images.

Instead, set your focal length for the shot, then use the camera's digital focus check punch-in function to set focus. That way you will have sharp images at the focal length you desire.

Hope this helps!

Cheers,

Paul :)
Click to expand...

Yes, I mean physically rotating the lens and zooming in! I thought all video lenses held focus throughout the range. Okay, so I should use the digital focus check instead?
Thanks for the reply.
 
I guess that would make sense because when I zoom in for tight shots, it's always super sharp, and when I zoom back out, I don't reset focus because I've always assumed it held focus - or that it was at least supposed to - despite having these recurring issues.
 
Is the newer version of this lens parfocal? Or is there a better parfocal zoom option out there for MFT? It seems as though this makes for a poor documentary lens.
The thing is, I've only noticed this problem indoors. I've shot run and gun stuff a lot with it and never had these problems.
 
Last edited:
Yes, definitely stop zooming in to focus. Use the digital camera check option instead.

Proper professional video lenses are mostly parfocal, but we're talking ones designed for video, not hybrid lenses like the Panasonic.

Parfocal is a big deal and if a lens is parfocal, it will usually advertise it loudly (and charge for it accordingly).

I'd imagine that the outdoor shots are probably at the infinity end, so the hyperfocal distance is probably helping to keep it more focused as you zoom back out.

HTH!

Cheers,

Paul :)
 
I'm okay with the lens not being parfocal, now that I understand that, and I'm not going to put a $30K lens on a GH4, so how about the Olympus I posted up above? It has nice specs and great reviews. Anyone here have experience with it?
Anything else in the same price range I should consider?
 
Before you spend money on another lens, I'd suggest you investigate the issues you have with the 14-140 first. Take a look at lens reviews to see if they are getting similar results. If you find that the images others are getting are sharper than the ones you're getting, then a new lens may not help.
 
The noisy images are partially due to the fact that it's an f4 to f5.6 lens, on a M43 sensor.

Personally I don't have any M43 lenses. Rather, I use a Metabones Speed Booster and EF mount lenses. In terms of light gathering capability, that means I can put an f1.8 zoom lens like the Sigma 18-35mm or 50-100mm, and get an effective f-stop of f1.2, which is around 10x more light hitting the sensor than the 14-140 f4, at f4 (more at f5.6).

Of course each person has different needs, but for me that combo far outweighs the compactness of M43 lenses, not to mention the nicer depth of field of a Super35 effective sensor area.

HTH!

Paul :)
 
Hi,

When you zoom in to focus, can you see the focus soften as you slowly pull back out ?
What happens when you let the camera control auto focus ?

Thanks,
Patrick
 
Last edited:
I don't think you mentioned whether you're shooting 4K or not. If not, you should be, even if you output 1080p: a full 50% gain in res., from a max of about 700 L/PH in mirrorless/DSLR native 1080p (and the GH4 is among the best) to a full 1080 L/PH in putting 4K on a 1080p timeline. The 14-140 is a pretty decent lens wide to mid-range, but softens a bit zoomed in with large prints - prob. not too obvious in video.
 
You must log in or register to reply here.
Back
Top