Laowa 25mm f/2.8 2.5-5x Ultra-Macro Lens Review

Macro_Cosmos · Post by **Macro_Cosmos** » Sun Dec 23, 2018 9:05 am

Been using this lens since about April, finally time permits me to write a review article. Published on my blog site.

I provide some photos and go through various aspects of the lens in detail. Any recommendations would be appreciated! First time doing this type of thing.

https://macrocosmosblog.wordpress.com/2 ... rm-review/

Thanks! Let me know if there's any factual errors or confusion in language.

Lou Jost · Post by **Lou Jost** » Sun Dec 23, 2018 11:22 am

That's a nice review (and I enjoyed learning the secret abilities of the Mitu 10x

)

One thing that surprised me is that you say diffraction becomes noticeable at f/5.6 for all magnifications. Diffraction is proportional to effective aperture, which increases rapidly with magnification. So the amount of diffraction at marked f5.6 should be greater at 5x than at 2.5x, and it should show up at wider apertures at 5x than at 2.5x. Can you check your observation?

ChrisR · Post by **ChrisR** » Sun Dec 23, 2018 1:38 pm

Nice review - it gives the impression of a decent lens at a fair price, especially for a relatively niche interest.

Adalbert · Post by **Adalbert** » Sun Dec 23, 2018 3:19 pm

Hello Daniel,
Very nice test, many thanks!
Actually I was interested in the comparison with the Mitty 5x. But you didn’t comment the results.
In my opinion Laowa is really good at 2.8 but Mitty is much better.
BR, ADi

Macro_Cosmos · Post by **Macro_Cosmos** » Sun Dec 23, 2018 10:20 pm

Lou Jost wrote:That's a nice review (and I enjoyed learning the secret abilities of the Mitu 10x )

One thing that surprised me is that you say diffraction becomes noticeable at f/5.6 for all magnifications. Diffraction is proportional to effective aperture, which increases rapidly with magnification. So the amount of diffraction at marked f5.6 should be greater at 5x than at 2.5x, and it should show up at wider apertures at 5x than at 2.5x. Can you check your observation?

Yeah, you're right. It could just be the lens being softer at f/5.6. It is a lot worse at f/5.6 and beyond, as illustrated by the wafer test shots. Whether this is due to diffraction or just softness in general requires some careful analysis. I'll make a followup with some test charts, setting up the shots is kind of an annoyance, as I don't have a good enough testing rig and ensuring that the chart is parallel to the sensor is tricky. The test could be misleading, I'm probably way too snobbish but that's what mathematics has done to me

Adalbert wrote:Hello Daniel,
Very nice test, many thanks!
Actually I was interested in the comparison with the Mitty 5x. But you didn’t comment the results.
In my opinion Laowa is really good at 2.8 but Mitty is much better.
BR, ADi

Absolutely correct.
You're right, I should have commented on the results. I'll update the post with some comments.

The Mitty hands down wins. It does always depend on the tube lens being used, I believe the tester was using a Raynox. I will ask him. But yeah at 5x, it is hard to beat the mitty. The mitty is a bit sharper, and excels in the control of CA and of course, resolution. I would even suggest that the mitty beats the Laowa when pushed down to 4x or even 3x; despite the vignetting.

399 is great price, however if one has connections in Japan, the mitty 5x can be had new for about 450-500 or so. Not inclusive of all forms of robbery and shipping. If any photomacrographers have the opportunity to travel to Japan, it's worth picking up new mittys. Gambling on fleabay isn't really fun.

lothman · Post by **lothman** » Wed Jan 02, 2019 4:45 pm

got the Laowa from a friend for some days, according to my resolution target 7-3 is 161 l/mm,
7-4 is 181 lp/mm,
7-5 is 203 lp/mm,
7-6 is 228 lp/mm.

Taken with a Sony A7riii at f2.8 and 5x.

Lou Jost · Post by **Lou Jost** » Wed Jan 02, 2019 5:03 pm

I don't recall seeing so much CA on mine, though I used a natural target with much less contrast.

lothman · Post by **lothman** » Thu Jan 03, 2019 4:33 am

Lou Jost wrote:I don't recall seeing so much CA on mine, though I used a natural target with much less contrast.

was late last night, since the pic was done with a negative Resolution Chart it was overexposed. Redone with 2 stops lesser exposure it Looks much better. I have no time for extensive testing but @2.5 I can distinguish the same fine patterns than @5x

Macro_Cosmos · Post by **Macro_Cosmos** » Thu Jan 03, 2019 8:42 am

lothman wrote:
Lou Jost wrote:I don't recall seeing so much CA on mine, though I used a natural target with much less contrast.
was late last night, since the pic was done with a negative Resolution Chart it was overexposed. Redone with 2 stops lesser exposure it Looks much better. I have no time for extensive testing but @2.5 I can distinguish the same fine patterns than @5x

Thanks for the post! Is that a Thorlabs target? How did you set yours up? I have a hard time getting mine to be perfectly parallel with the image sensor.

lothman · Post by **lothman** » Thu Jan 03, 2019 4:36 pm

Macro_Cosmos wrote: Thanks for the post! Is that a Thorlabs target? How did you set yours up? I have a hard time getting mine to be perfectly parallel with the image sensor.

It is this target Ebay Link

Yeah adjusting is quite some effort

lothman · Post by **lothman** » Thu Jan 03, 2019 4:40 pm

@5x f between 2,8 and 4 click, 55 images:

and a crop

This was also a quick test, but @5x I think there is empty magnification, at least at the Sony A7riii.

Macro_Cosmos · Post by **Macro_Cosmos** » Fri Jan 04, 2019 12:17 am

lothman wrote:@5x f between 2,8 and 4 click, 55 images:

and a crop

This was also a quick test, but @5x I think there is empty magnification, at least at the Sony A7riii.

Is that fungus of some sort? Looks kind of appetising!

What do you mean by empty magnification? It looks quite okay to me, mine wouldn't be better or worse.

lothman · Post by **lothman** » Fri Jan 04, 2019 4:36 am

no no fungus it is a burn match. With empty magnification I mean that at 5x the picture is bigger but does not have more information, so at pixel level it looks somehow soft. On the resolution target the finest detail I could distinguish was the same at 5x and 2.5x on my limited setup. Yesterday I handed the lens back to my friend so I cannot do further tests.

RobertOToole · Post by **RobertOToole** » Fri Jan 04, 2019 8:02 pm

lothman wrote:no no fungus it is a burn match. With empty magnification I mean that at 5x the picture is bigger but does not have more information, so at pixel level it looks somehow soft. On the resolution target the finest detail I could distinguish was the same at 5x and 2.5x on my limited setup. Yesterday I handed the lens back to my friend so I cannot du further tests.

Like your subject choice Lothman, lots of nice details and textures.

I need to borrow the idea sometime.