Laowa 25mm f2.8 macro review
Laowa 25mm F2.8 2.5-5X Ultra Macro review
Venus Optics’ extreme macro lens
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The Venus Optics Laowa 25mm macro lens is a specialist manual focus macro lens.
It offers magnification from 2.5x to 5x with a nominal aperture of f/2.8 at its widest.
Mount options include Canon EF, Nikon F, Sony FE and Pentax K.
Keith has been testing a pre-production unit looking just how you use such a lens.
The lens body is all metal construction and gives a very solid feel.
It’s fully manual, in that there are no electronics in it, so no auto stopdown of the aperture, no EXIF data and absolutely no auto focus.
In fact if, your experience of macro is just the closest focus of a normal camera lens, then expect to learn a whole load of new skills as you enter the world of the very small.
Here’s the 25mm on the front of my Canon 5Ds, the 50MP full frame DSLR I’m using for my testing.
[you can click on many of the images in the review to see them at a larger size]
This is at a magnification of 2.5x.
There is no focus ring on the lens – like any macro lens at this magnification, you move the whole camera to focus on an object.
The ring you can see towards the middle of the lens is to adjust the magnification.
Here it is at 5x.
The other ring is for setting your aperture from f/2.8 to f/16
The 8 blade aperture gives fairly good out of focus (OOF) highlights, as I’ll show later, comparing with the 6 of my own Canon MP-E65mm lens
Set at f/8
At the other end, there is a rectangular baffle, which helps cut down reflected light (often only seen in images as a reduction in contrast).
The baffle is level with the mount at 2.5x
The lens comes with a metal bayonet fit lens cap.
Whilst not available for testing there will be an optional LED light unit.
There will also be a Arca Swiss style lens tripod mount option – this photo shows a sample model. It may differ slightly in production.
The lens specs, as published.
Note the difference between focus distance and working distance.
One is the distance from focal plane (back of the camera) to subject, whilst the other is the gap from lens to subject.
Here’s the working distance at 5x
The Lens MTF chart reflects my experience that performance is very good over the entire field and only drops off slightly right at the far edges.
There are quite a few things you need to consider when working at the magnifications this lens offers.
BTW I’m aiming this at readers who may have dabbled in close-up photography but with nothing more than close-up focus. My apologies to real macro experts for glossing over some of the finer details, but you already know all this stuff…
First up, depth of field (DOF).
Essentially there isn’t any. This view of a US coin at 5x magnification and at f/4 shows just how thin the zone of sharp focus is.
[Click to enlarge to 3000px wide view]
Remember that the lens magnification is the magnification of the image on your camera sensor compared with real life.
So the 5x field of view is 1/5 of my frame width (36mm) or 7.2mm on my 5Ds.
It’s proportionally less for smaller sensors.
Secondly – what aperture?
You’ll have noticed that focusing close with a normal lens gives a thin depth of field, but you can always stop down and use a smaller aperture.
Well, you can do that with the Laowa 25mm, all the way to f/16.
But, and it is a big but, apertures set on the lens are not the aperture that the lens is working at.
The effective aperture is given by taking the set aperture and multiplying it by 1 plus the magnification.
So, at 5x and f/11, the effective aperture is (5+1) x 11 or f/66
If you are taking just a single photograph then diffraction softening is visible, if you look carefully, at f/4.
By f/11 or f/16 the depth of field is larger, but image softness is a serious issue for me.
My own macro use. I should note that I include studio macro photography in the commercial photography work I do. It tends to be shots of very small electronic and mechanical parts. As such, finest detail is vital so I stack images to get DOF. That and the fact that it’s winter also explain why there are not photos of bugs/flowers/fungi in this article – these seem to be the staple of most macro forums, but I’m sure examples aplenty will appear once the lens is widely available.
Lighting, exposure and focus
Other than at wide apertures, the viewfinder view is rather dark, so hand held shots are tricky if you were working at f/8-11, where the lens needs manually stopping down.
The magnification makes for very visible camera shake, so unless you have very strong continuous lighting, flash is essential.
With no lens adapter to try, I used a Canon MT-24EX macro flash, with the flash heads on separate supports.
This for an oblique view of the memory module.
I did try the lens with the KF-150 ring flash I tested recently, but the flash needed it’s own support.
An adapter from the lens cap bayonet fit to say a 58mm thread would make it easier to use in the field with flashes like the KF-150 and the Canon MT-24EX. Whilst no great use in the studio, it might be of interest to those working outdoors.
The Laowa KX800 flash, with the small soft-boxes fitted, gives a very smooth light without strong shadows.
I’ve a review of the KX800 flash, which is one Karen particularly likes for some of her jewellery photography.
Exposure is something I prefer to set manually, as with flash power output settings.
Since the lens doesn’t tell the camera the aperture, or even that it’s there, TTL metering modes are somewhat unpredictable.
It’s actually quite tricky to evaluate details of lens performance for a specialist lens like this.
I don’t have an optical bench for precise alignment, so what would seem like a simple task of taking a photo of a flat object is very tricky, given the limited depth of field.
Take this shot of part of a memory module (sodimm) at f/2.8
It’s actually from the working distance shot earlier in the article.
No, I could have levelled it a lot better, but still I’d not be certain it was spot on. There is also the fact that the DOF is thinner than the vertical height of the components.
Stacking a hundred shots at f/2.8 (using Helicon Focus with a Stackshot macro rail) gives me this version.
The image here is reduced to 50% of the 50MP frame size [click to enlarge]
The stacking does show some slight softness in the corners.
However, looking at individual frames, the actual amount of softening is best shown in the bottom right corner (compare edges of the gold strips)
This is a 100% crop of the stitch with a size bar. [click to enlarge]
One nice feature of Helicon Focus is that you can get a depth map of the image and use it to animate your image.
Stacking at f/2.8 and 5x to get this shot of a power control chip on a match head
A 100% crop shows the amount of detail, and the ever present problem of dust.
The shiny solder balls show a bit of colour fringing, but this is partly from the stacking and image blending.
For positioning items like the chip below you need a fine needle, and I need to put on a second pair of reading glasses to see it.
The chip is shown next to the raised date lettering on a credit card.
This shot (>100 stacked images) shows a number of problems.
The stack doesn’t cover the entire depth of the view I want. The lighting is too simple – I need a bit of shadow to emphasise the heights of the chip and number. The stacking has a number of errors from the reflections of lights.
There is also too much dust, and the silver finish has been rubbed off the top of the ‘4’.
So – why include a ‘dud’ like this?
Well, the actual shots that make it up are technically sharp and full of detail (all at 5x and f/2.8)
Any problems come from composition, lighting and processing.
Just buying a great macro lens does not make for great photos… expect to spend a lot of time experimenting.
Whilst the results are what matter to me in the final analysis, I still needed to have a bit more of a look at individual shots at different settings.
Test shots at different apertures
The memory module has some very fine detail and is reasonably planar.
I’ll show a series of photos looking at the centre chip on the board.
Here are views at 2.5x and show that if you only want smallish images for web use, then f/16 isn’t as bad as the maths might suggest. [click to enlarge]
Now a set at 5x
For completeness, I also have test sets for 4.5x, 4x, 3.5x and 3x…
I’ll leave them aside though, since they tell me that the lens works pretty much the same at all magnifications.
Maybe sharpness is slightly better at one magnification than another, but I couldn’t see it.
I also got the distinct impression that at f/2.8 I’d see even more detail if I had a 100MP sensor in the camera.
I’ll finish up this section with a look at 100% crops from the point I focused on.
Helicon Remote and the Stackshot motorised rail lets me position the camera/focus and take the shots.
Sample gallery of crops – click on any image to open gallery.
When looking at the smaller apertures, you really do see the choice you are making between depth of field and diffraction softness.
If you’re a regular visitor, you’ll know I rarely do comparative reviews (why?). However, since I happen to use Canon’s specialist MP-E65 macro lens for my work, I was curious to see how well the Laowa did.
The MP-E goes from 1x to 5x, has auto aperture control, and a 58mm screw thread at the end (for flash or the specialist lens hood you can get) which makes it more versatile for some usage scenarios. See my look at the MP-E65 a while ago for more.
Note: That’s only more versatile for me with my Canon DSLR – I don’t have any other cameras to test with, so this is a moot point if you are using the Nikon/Pentax version and depends on what adapters you have for Sony.
Size wise at 1x it dwarfs the Laowa (at 2.5x)
At 5x, you can see how much both lenses extend.
The ‘pointy end’ of the Laowa looks somewhat easier to get into small spaces, but you do need to consider lighting as well.
The working distance of the Laowa is a tad longer than the Canon (at similar magnifications), which coupled with the smaller diameter might make lighting a bit easier.
However, I was more interested in image quality.
The 8 blade aperture of the Laowa gives better shaped out of focus highlights [click to enlarge]
I’m minded to observe that the fine detail of the Laowa just pips the MP-E, but at f/5.6 we are seeing softness from diffraction setting in.
Another pair of comparisons 5x at f/2.8 shows the slightly higher magnification of the MP-E and the slightly warmer colour rendition of the Laowa.
Lastly a comparison at 5x and wide open at f/2.8 [Click to enlarge]
Two shots of the whole field of view – first the Canon.
Secondly the Laowa.
Now, 100% crops – first MP-E65mm
Second, the Laowa 25mm.
The simplest answer to the comparison question is that if I needed to photograph some items for a job, then for 1x to 2x the MP-E would be used, whilst for 2.5x to 5x the Laowa would come out…
The good thing is that when the Laowa 25mm goes back the MP-E will still be used…
Some more Laowa images
Cracking the top off a 197o’s Intel 8255a PIO chip gives me this view, including the dust from breaking the seal and some of the broken connecting wires. This image [click to enlarge] is only 3000 pixels wide, the full size version ~8500px.
It’s a stack of ~150 images.
What about a few single shot views?
It’s snowy outside, so not much in the way of bugs and flowers.
I tried a shot of a roast coffee bean, but it’s too big to fit the frame at 2.5x and frankly, coffee beans don’t look like coffee beans at that size…
Some fennel seeds – this is a single shot at f/8 with the same dual head flash setup as before.
The softness is there at full resolution compared to f/2.8, but the out of focus zone has not been blurred too much.
If you’re doing ultra fine detail work, then the lens is superb at f/2.8, but don’t be put off by worries over diffraction, especially if your pictures are going to be downsampled to just a thousand pixels wide or so and sharpened.
Two views of my mechanical stopwatch.
The first is taken at 2.5x at f/8, whilst the balance wheel is at f/11
The lighting is using the Laowa flash with the small soft boxes.
An Ethernet plug ~3x @f/11
Macro photography at this scale is not a simple operation.
From an image quality point of view, there was little I could fault the lens with. It shows a slight bit of longitudinal chromatic aberration (purple/green tinges to OOF areas), but not excessive. The 8 blade aperture gives better looking OOF highlights than the 6 bladed Canon MP-E65mm.
Perhaps the only area that may concern some is the lack of stop down, meaning that it’s either a dark viewfinder at smaller apertures or you have to stop down manually before the shot. It’s no problem for my sorts of use.
The magnification setting is firm but I did notice that careless adjustment of the aperture could easily lead to a slight change in the magnification setting, and hence move the plane of focus. This was worse when the lens was pointing downwards [do note though that this was a pre-production lens]
The build quality of the lens feels good and the sample I tested came in a soft neoprene bag.
Ultimately this is a lens you’ll want for fine detail, and it definitely delivers.
The lens has a list price of $399
If you’re curious about macro and photographing small stuff, have a look at the collection of articles in the Macro Category of articles – all categories in the drop-down list at the top of the RH column on the page.
See also Keith’s interview with Venus Optics– looking at their lens design philosophy.
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