2x Lens Test: Anyone Have Time For a Quick Look?

[rjlittlefield]

For fun I ran "effective aperture" and "Effective focal length" in Google.
EA: 229,00 results
EFL: 409,000 results

Responses vary by questioner!

For me Google gives:
"effective aperture", "About 196,000 results", and the first page is all about RF antennas, not optical lenses.
"effective focal length", "About 572,000 results", and hit #3 explains that "Effective Focal Length (EFL) is the focal length affected by the camera’s crop factor." (The other hits on first page refer to the same EFL that we're talking about.)

--Rik

[RobertOToole]

For fun I ran "effective aperture" and "Effective focal length" in Google.
EA: 229,00 results
EFL: 409,000 results

Responses vary by questioner!

For me Google gives:
"effective aperture", "About 196,000 results", and the first page is all about RF antennas, not optical lenses.
"effective focal length", "About 572,000 results", and hit #3 explains that "Effective Focal Length (EFL) is the focal length affected by the camera’s crop factor." (The other hits on first page refer to the same EFL that we're talking about.)

--Rik

Interesting Rik!

My first front page is all optical websites, maybe they are custom filtering or something?

I should have searched in a incognito window or If I log in under a business account (google) it supposedly doesnt filter or tailor/skew results.

I have to be careful searching for things to get true results when I am searching for something, lets say when I've traveling etc or looking to see a site ranking (it will not rank accurately).

Best,

[rjlittlefield]

My first front page is all optical websites, maybe they are custom filtering or something?

I expect.

I've done a number of searches lately related to antennas and transmission lines. So I imagine that Google has noted that I click on those articles, and has silently updated my profile to reflect that interest.

When I do a (supposedly untracked) query through duckduckgo.com, "effective aperture" gets me a mix of stuff about antennas and optics, plus one hit on beryllium windows for ultra-high-vacuum systems, all on the first page.

Under normal circumstances, of course I would like to know about things that are related to my interests.

But this search-bubble effect means that I have learned to write "when I ask Google", as opposed to "if you ask Google". I have also learned to become very suspicious when searching for anything that may involve an opinion, but that's a topic for some other forum.

--Rik

[lothman]

Hello Robert,

I read with great interest and haven't found anything to be corrected. May be one question: did you remove the filter from the Laowa they put on for dust protection? This might affect image quality a little.

With some patience you can get a used Laowa for a good price and to squeeze out the last percent in image quality with another lens you probably have to spend double/triple the money

If you are not going to use it at m>1, I would think the 70mm Sigma Art lens would be considerably better, and not much more expensive.

can you please define "considerably"? I think the Laowa is already at such a high level, that improvements are only visible in very demanding applications on high resolution sensors. Of course the Sigma has AF and automatic aperture.

regards
Lothar

[chris_ma]

If you are not going to use it at m>1, I would think the 70mm Sigma Art lens would be considerably better, and not much more expensive.

can you please define "considerably"? I think the Laowa is already at such a high level, that improvements are only visible in very demanding applications on high resolution sensors. Of course the Sigma has AF and automatic aperture.

I also can‘t imagine there‘s much difference, maybe lou was talking about the corners (but the sigma 70 shows some fall off in the MTF curves as well).

I would manly use it for repros and copy stand animation work, so in the 40x30cm to 15x10cm range, and for that a fully manual lens could have some advantages too since it‘s easy to adapt to different camera systems and a manual aperture will eliminate any risk of flickering on animation films.

Actually that‘s an interesting question for stacking too:
Has anybody ever had problems with slight exposure fluctuations on long stacks due to the jumping aperture, or ever worried about wearing out the lens diagram motor?

[Lou Jost]

Chris and Lothman, I can only go by my own experience with the Sigma and Robert's tests. Missing is a direct comparison at 1:10 with the Laowa. However, in general a lens designed for the range of 2x to infinity has to make some design sacrifices that a lens designed for 1x to infinity would not have to make.

Sigma makes a Canon to E mount converter and a Canon to L mount converter that preserves most automation, so a Canon mount is a good choice. However, my favorite feature of the Sigma lens is the ability to do automatic focus stacking by ring, with a suitable camera. This is a huge benefit. In the case of Panasonic L mount cameras, the lens has to be in L mount for this to work.

It is nice to have the option of auto-focusing, especially if you have a big set of paintings to copy in different mounts/frames.

Lou

[RobertOToole]

Hello Robert,

I read with great interest and haven't found anything to be corrected. May be one question: did you remove the filter from the Laowa they put on for dust protection? This might affect image quality a little.

Excellent question! ( I need to add a note on this)

When I received the Laowa 2x before the holidays (BTW I am going to buy this copy from the owner it turns out!) I tested the lens at 1x against my best lenses ( results coming soon) with and without, and I could not tell any difference, but as a general rule I as a professional photographer to never use a filter unless I have some compelling reason (PL=to kill reflections) so I left it off for the tests. It shouldn't have any effect as far as I can tell.

With some patience you can get a used Laowa for a good price and to squeeze out the last percent in image quality with another lens you probably have to spend double/triple the money

Agreed 100%.

BTW, the owner gave me a nice offer, and I'm glad to take it since this lens is not suffering from any de-centering or anything else.

If you are not going to use it at m>1, I would think the 70mm Sigma Art lens would be considerably better, and not much more expensive.

can you please define "considerably"? I think the Laowa is already at such a high level, that improvements are only visible in very demanding applications on high resolution sensors. Of course the Sigma has AF and automatic aperture.

After testing both Art lenses and the Laowa 100mm, I would say if you need AF (I know I do) go with a Sigma Art, if you are happy with MF, the Laowa is a fine lens and you won't be giving up much. The differences between the Art and Laowa are so small, a lot of people could'nt tell the differences I don't think. I did test the two vs the PN105A and will try to get the results up ASAP (the results are up already online on an unfinished page with placeholder text).

Best,

Robert

[RobertOToole]

Chris and Lothman, I can only go by my own experience with the Sigma and Robert's tests. Missing is a direct comparison at 1:10 with the Laowa. However, in general a lens designed for the range of 2x to infinity has to make some design sacrifices that a lens designed for 1x to infinity would not have to make.

1:1 comparison results coming soon!

For the record there is a difference in IQ, the Sigma being better, but the Laowa is closer than I thought it would be for sure. I would highly recommend either or both lenses without hesitating even with the focus-by-wire of the Sigma and the poorly designed focus ring of the Laowa (to get 1:1, the indicator on the ring has to point to the 1 on 1:1 (not the colon) also 2:1 is really 1.95:1 on my lens)

Sigma makes a Canon to E mount converter and a Canon to L mount converter that preserves most automation, so a Canon mount is a good choice. However, my favorite feature of the Sigma lens is the ability to do automatic focus stacking by ring, with a suitable camera. This is a huge benefit. In the case of Panasonic L mount cameras, the lens has to be in L mount for this to work.

That is the Sigma MC-11. https://www.sigmaphoto.com/mount-converter-mc-11

I use an MC-11. Works perfectly and preserves most lens functions, very well made and updatable over the Sigma USB dock: https://www.sigmaphoto.com/sigma-usb-dock
The MC-11 confirms function compatibility with a lens via LED, green yes, orange needs an update, red is functions can't be guaranteed.


Best,

Robert

[RobertOToole]

I also can‘t imagine there‘s much difference, maybe lou was talking about the corners (but the sigma 70 shows some fall off in the MTF curves as well).

I tested the Sigma Art 70 in 2020

It beat all the lenses in the test at 1x other than the PN105A. IQ was better than the APO-Lanthar 110 and 125 (my APO-Lanthar 125 is very sharp) at 1x. The MacroVaron came in 3rd beating the Sigma Art 70 in the corners slightly but the Sigma was better than the SK lens in the center by quite a margin.

Sigma Art 70 is upper right corner in the photo.

I would manly use it for repros and copy stand animation work, so in the 40x30cm to 15x10cm range, and for that a fully manual lens could have some advantages too since it‘s easy to adapt to different camera systems and a manual aperture will eliminate any risk of flickering on animation films.

Actually that‘s an interesting question for stacking too:
Has anybody ever had problems with slight exposure fluctuations on long stacks due to the jumping aperture, or ever worried about wearing out the lens diagram motor?

Electronic is a little bit better with this, but either mechanical or electronic, it can be an issue. One way to stop it? Set the aperture, disconnect the lens to the point where it loses electronic contact so the lens stops down. This locks the iris stopped down. Time lapse photographers do this to save themselves all the correction work in post. (mechanical iris lenses need to have the level locked down). This trick also works when reversing lenses also, set, remove the lens, it should lock to the f/stop when you remove the lens with the camera power on (at least on the cameras I've tried, your mileage may vary). I just thought about it, I've only used this on vertical stands, this trick might not be safe on a horizontal setup now that I think about it.

Best,

Robert

[Macro_Cosmos]

Out of curiosity, I searched for "effective focal length" and "effective aperture" with several browsers.
In bold are the ones I use.

Google (yuck), EFL (which I don't use): Top 3 results are unrelated advertisement, from Edmund Optics, Adobe and some point-and-shoot thing.
Then Wikipedia, then a bunch of photography related bluff. The useful result is on page 2!!! How?
EA: Useful result on page 3 (!!!!), the rest are antenna related. The page 3 result is basically a B&H advertisement.

Assume page 1...
Duck.com, EFL: Useful results from the first entry of the first page.
EA: First 4 were antenna related, 5th is the B&H article, then a mix.

Yandex.ru, EFL: Very first result is useful, same as duck.com
EA: Antennas, then the B&H article

Bing, EFL: Same story as above
EA: Antennas, and a couple useful ones on page 1. No B&H article.

Swisscows, EFL: ditto
EA: Antennas, B&H article.

searX instances, EFL: ditto
EA: Lots of antennas and a some useful ones.
EA, science tab: mix of antennas and optics.

Yeah, I am staying away from Google.

[RobertOToole]

Yeah, I am staying away from Google.

I try to when I can, I like Brave browser and their search engine its anon., transparent results using their own index, and private.

Best,

Robert

[yiyi]

hello, i need the password ,thanks

[chris_ma]

Yeah, I am staying away from Google.

strange, when I do a search all the results on the first page are totally relevant:
4 technical knowledge articles, 2 edu papers, 3 calculators and a forum discussion.

not that I'm a big fan of googles data gathering, but I haven't found an alternative which gives me as fitting results.

[Macro_Cosmos]

Yeah, I am staying away from Google.

strange, when I do a search all the results on the first page are totally relevant:
4 technical knowledge articles, 2 edu papers, 3 calculators and a forum discussion.

not that I'm a big fan of googles data gathering, but I haven't found an alternative which gives me as fitting results.

Yeah, it all depends on how you use it. I have not used Google for a long time and opted out of all their spooky data stealing options, the results are completely weird.
Google does tailor their search results. I can expand on Rik's "opinion" point but as stated, it is for another forum. Different search engines are good for different purposes, Bing's image search is really good, they allow categorising images by size and many other metrices right from the UI, whereas for Google, one must use the advanced search option.

duck.com has a location option, using that gives better results than Google when it comes to news and opinions, as they have no intention to censor results on behalf of all those spooky alphabetical guys.

[kaleun96]

Great test and write-up Robert, I had been waiting for this one! I'm pleased to see I can stick with my Laowa and not bother chasing any further improvements on optical quality at 2x for the time-being. I've been using this lens for about two and a bit years now and it has performed wonderfully, I just wish the Sony version had electrical contacts for aperture and EXIF.