poor image quality from laowa 25mm + olympus

[pu5z3k]

Hello,
I have had a 25mm laowa lens in my backpack for a long time
Unfortunately, there was never an opportunity to test it, until the last outdoor session, after which I am very disappointed.

The image quality is, in my opinion, very unsatisfactory - so I start by looking for the problem not in the lens, but in the technique of taking pictures.

this how my backstage looks like:
backstage - laowa stacking by Radoslaw, on Flickr

i use an adapter to attach the lens to the olympus camera.
In addition, I covered the adapter with a black flock to avoid unnecessary light.

this is a single frame at 3x with f4
laowa single frame by Radoslaw, on Flickr

and here is stacked picture at aprox x5 and f5.6
laowa stacked image by Radoslaw, on Flickr

in my opinion, there is no question of any image quality.
I will add that when using flash, this problem does not occur - at least to an unnoticeable degree for me.
I am asking you for help in finding a solution.
Best regards,

[Guppy]

Hi
Probably strong light from the side, try a lens hood,
or lens shadowing.
Kurt

[Macro_Cosmos]

I recommend F2.8 since you are focus stacking. The difference between 2.8 and 5.6 is significant. Perhaps more diffusion will make the light softer.
I would also get rid of the ballhead to mount the rail directly onto that geared/three-way head.

[Lou Jost]

I have very good results with the 2.5x-5x Laowa, especially at the lower end of its magnification range. The ability to change m continuously allows me to frame subjects more precisely, better filling my FF semsor. And it is soooo convenient and easy. It makes images that are publishble in coffee-table book size. I use an aperture of about one-third of a stop closed down from f/2.8. I have no flare problem. I have modified it by adding a step-up ring so that I can attach filters.

[Adalbert]

Hi Lou,

I have modified it by adding a step-up ring so that I can attach filters.

Would you please show a picture of your solution?
Thank you in advance,
Best, ADi

[Lou Jost]

Sure, I'll take a photo tomorrow.

[Guppy]

Hi

This is what my lens hood looks like
Plastic lens cap with hole and Hi-tack flocked light trap material; self-adhesive
https://www.fpi-protostar.com/hitack.htm





Kurt

[Lou Jost]

Adalbert, here is my solution, an epoxied Sensei 46-43mm step-down ring. It is not perfect, a filter attached to this does not screw in completely, but it is good enough to hold it. I choose this ring because it does not restrict my lighting angles much, and it mounts perfectly flat on the Laowa.

[Adalbert]

Hi,
Is there a technical reason why the Laowa does not have any thread for the filter?
Best, ADi

[Lou Jost]

I suppose it is not designed to shoot through glass. But above f/2.8 I doubt that it matters much.

[pu5z3k]

ok so i try my way and design filter mount - and print it

here is result:
laowa 25mm filter mount by Radoslaw, on Flickr
if someone is interested of 3d model i can send via email

[chris_ma]

might be worth trying a lens shade too (rolled black paper usually works ok)

[Medwar]

I think the reason can be that with 5x and F5.6 the lens is too far in diffraction territory.
If shoot it this mag, try to shoot fully open.

According to calculations I did for my Panasonic G9 (same size and similar MPix sensor),
Fe = M * (F/pf +1),
where Fe=effective f-stop, F=f-stop, pf=pupil factor, M-magnification.
So F/5.6 at 5x equals effective F/33.6 (I don't know the real pupil factor of laowa, so I put it as =1).
And on MFT sensor I get the best sharpness at effective F/9.1 (tested on G9 in high-res mode), and then diffraction begins to step in.
So, according to this my calculation, Laowa F/2.8 in theory should be diffraction-limited from 3x+ even when fully open (F/2.8 ) , when used with 20Mpix MFT sensor, which has really small, 3,34 micron pixels.