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Laowa 100mm f/2.8 2X Ultra-Macro APO review

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Review: Laowa 100mm f/2.8 2X Ultra-Macro APO

Manual focus 100mm lens close focuses to 2x


Keith has been looking at a new manual focus macro lens, the Laowa 100mm f/2.8 2X Ultra-Macro APO.

Venus optics has made a name for itself producing specialist lenses, especially in the Macro area.

The lens has been tested on Keith’s usual Canon 5Ds (50MP) and the new Panasonic Lumix S1R, offering a multishot imaging capability of ~187MP, a massive resolution for a 35mm sensor.

For lens ordering/info see Venus Lens

100mm lens-and-box

The 100mm f/2.8 2X

The lens looks quite long for the focal length, but this comes from the significant movement of the optical components as you focus to its closest point.

laowa-100

It’s shipped in a well padded box – the Canon mount version is auto aperture, with no aperture control ring.

100mm lens-and-box

The focus movement is smooth, giving a very good feel to fine focussing. The focus throw is around 120º with no backlash or looseness in the movement.

The movements of the front and back elements are noticeable.

Here’s at the infinity setting:

front infinity

rear infinity

Whilst here’s the lens set at its closest focus distance (2x).

Note: The 2x magnification means that the image of your subject on the sensor is twice life size. At 1x or ‘life size’ the field of view at the plane of focus is the size of the sensor, or 36mm x 24mm for ‘full frame’ (so an object 18mm x 12mm fills the frame at 2x).
There are lots of reviews and articles about macro photography here in the Macro Category, if you want to learn more (including ‘making your own’ macro lenses).

front-2x

rear-2x

The movement of itself is not an issue (many macro lenses extend rather a lot) but if you are working outside take care to keep the inside of the lens barrel clean.

Lens mounts and adapters

At the time I was testing the lens I happened to be looking at the Panasonic LUMIX S1R full frame mirrorless camera. Now, this uses the ‘L’ mount, but I happened to have the Sigma MC-21 EF adapter here.

This is from taking a close up photo of a processor chip. The blue marks on the chip are from the manual focus peaking highlights for the S1R.

The S1R has sensor stabilisation, making hand held use of the 100/2.8 rather easier (but there are limits to what IS will do).

panasonic-s1r-macro

Another camera I tried was my EOS RP (full review) which comes with an EF->RF lens adapter.

‘Only’ 26MP and without image stabilisation, you need to be a bit more careful using it, but the focus peaking available in the viewfinder makes lenses like this a lot easier to use for non-studio macro work than my EOS 5Ds.

A hand held shot of a flower on the small citrus plant on our kitchen windowsill. This is f/5.6 to get a usable depth of field, although 1/60 is just too low (ISO 640) and there is a bit of blur.

citrus flower

A detail from a photo of one of my cacti, after watering, taken handheld with the S1R shows no blur.

cactus-watering

The lens specifications

As mentioned, the lens is manual focus only

Name 100mm f/2.8 2X Ultra-Macro APO
Focal Length 100mm
Max. Aperture f/2.8
Angle of View 24.4°
Format Compatibility Full Frame
Lens Structure 12 elements in 10 groups
Aperture Blades 9 (Canon), 7 (Nikon), 13 (Sony FE)
Min. Focusing Distance 24.7cm (2X)
Max. Magnification 2:1
Filter Thread 67mm
Dimensions Ф72 x 125 mm
Weight 638g
Mounts Canon / Nikon / Sony FE

The construction is quite complex (green is extra low dispersion glass)

lens construction

The available MTF data shows performance at different magnifications. Don’t read too much into these figures other than suggesting that macro performance at 1:1 is rather good (yes it is) and that the lens is no slouch at 2:1 and in ‘normal use’ as a straight 100mm lens

1X MTF2X MTFINFINITY MTF

The aperture blades at f/8

aperture blades

Using the lens

The lens is clearly marked with reproduction ratios as well as distance information. Remember that distance info is from the sensor plane, usually marked with a ‘crossed O’ symbol as seen here on the 5Ds [top left].

reproduction-ratios

Even at 1:1 or ‘life size’ the lens front element is retracted quite a bit.

1:1 or life size

The front working distance is quite good, seen here at full 2x magnification.

testing setup

There are depth of field or DOF marks on the lens suggesting the sort of range of sharpness you can expect.

dof-marks

However I’d note that these are generous, and especially with higher resolution sensors, the actual depth of sharp focus will be less than you see here.

The effects of aperture

Using the memory module shown above, and photographing with the 5Ds at an oblique angle shows the depth of field and how out of focus areas are rendered. This is at 2x magnification and includes shots at f/2.8, f/5.6, f/11 and f/22

First, the whole frame (click on any image to enlarge)

f2.8

F/2.8

f5.6

 

f11

f/11

f22

f/22

Note that these images are shot at maximum (2x) magnification, which I suspect is closer to the usage most people will be interested in.  The lens shows some increased vignetting wide open, as you move to using it at longer distances, but levels of distortion and especially residual chromatic aberration are low.

For more general close-up work, such as the group of orchid flowers below, the lens shows an improved image quality over the full field stopping down to f/5.6

BTW If you see measured MTF charts in reviews of this lens, do pay careful attention to the conditions they were measured under – this lens simply doesn’t perform the same at infinity as opposed to close up at 2x

Now for 100% crops of the photos above – basic RAW processing with ACR in Photoshop CS6.

These crops are ~2k pixels across, so click to enlarge

f2.8 crop

f/2.8

f5.6 crop

f/5.6

f11 crop

f/11

f22 crop

f/22

Here’s the right edge of the frame at f/2.8 at 100%

side of frame f2.8 crop

Some stacking

As you can see above, stopping the lens down at high magnification, quickly reduces resolution and contrast in the image. This softening from diffraction may not matter too much with some subjects (and final sizes of images you’re using) where going to a smaller aperture is simply needed to give a workable depth of field.

If you’re using a 50MP sensor, then the change from f/2.8 to f/4 is just about visible. If you’re creating images at almost 200MP, then it’s clearly visible.

On way I get round this for some of my commercial macro photo work is to stack images taken at slightly different camera positions. The camera in the examples above is mounted on a StackShot motorised rail (itself on a big studio stand). I control the process with the HeliconRemote software, and stack resulting images with HeliconFocus. The control software operates the Stackshot rail.

A simple photo of one of the orchid flowers that’s just opened on our kitchen windowsill.

This is the view of the nearest point of the flower

orchid-close

and this is the furthest away point I want

orchid-far

I’ve set the controller to take 50 shots between near and far points. I’ll then stack them to get an image with enough depth of field.

The photos are taken at 1/15s and f/7.1.

Hang on – didn’t I just say that not shooting wide open lost detail? Well yes it does – particularly at 2x magnification. However this shot is around 0.4 magnification and I want enough depth of field that 50 shots will overlap enough not to produce banding when stacked. Banding can come from not quite taking enough shots to fully overlap really sharp parts of the image.  Your choice of aperture should reflect what you want to use the photos for and how you intend to process them. Be very wary of any suggestion that you should use a particular aperture – you need to experiment and get a feel for what works.

Here’s a stacked result, cropped square. It could comfortably be printed at 24″ square, and given the detail I’d be happy if someone wanted a 60″ square version (although I’d probably us Gigapixel AI to resize and print it on an Epson P20000)

orchid flower

Have a close look at this teaspoon of small electronic components. In particular look at the back of the furthest chip.

Those lines are a result of not using a fine enough step for each picture of the stack for the aperture I was using. Now, I could easily fix that in Photoshop, or I could have taken a bit more care in the original photo capture settings…

chips on spoon

There is a lot of detail in the 50MP images from the 5Ds, and you can freely crop as needed.

Some fennel seeds…

fennel seeds

Actually just a crop from this 50MP image

seeds-in-spoon

The stacked images (70 of them) were taken at f/2.8

Here’s just one.

individual-fennel-seeds-photo

and a 100% crop of the single image.

cropped-individual-image

Of course, when not quite so close, just stopping down a bit may well suffice.

These orchids (f/11) taken with the 5Ds have more than enough detail for a 16″ x 24″ print for Karen’s Mother (who grows them rather more seriously than I do).

orchids

This one taken using the Laowa KX800 dual flash I tested some time ago.

flash setup

Note that the flash is mounted on the camera. This is fine for single shots, but if I’m stacking, I’ll mount the flash externally and connect with an extension cord. I don’t need the lighting to change between images for stacking.

Really high resolution

I’m currently testing the Panasonic S1R and with the Sigma MC-21 EF->L adapter, the 100/2.8 works really well. I’ll look at this in my upcoming review notes for the S1R, but I was pleased at how well the new EF mount Laowa lens worked with the Panasonic camera.

The multi-shot mode of the camera shifts the sensor a small amount and gives the equivalent of a single ~187MP image from 8 shots taken in quick succession. For best results you need a sturdy camera mount since it won’t take much vibration or subject movement to cause issues.

However, the detail is impressive.

This is the full frame image, of an old micro chip (an 8255A)

8255-full-frame

It’s ~187MP so a lot of detail.

This next image is a 50% magnified crop (click to see enlarged).

8255-hr-crop 50percent

Suffice to say, when using multishot for macro work, it really helps not to have other people walking round the house – our 1888 floorboards and joists are not ideal for precision macro work…

This shot was also good for showing just how little chromatic aberration the lens exhibits

These two shots show (at 100% for a 47MP image) how a bit of adjustment in ACR helps with RAW processing.

First, the shot with no adjustments

no CA correction

Secondly with a small amount of correction.  Were it not for my deliberate choice of very fine detail, you’d likely not even notice anything to correct.

minor CA correction

Conclusions

The lens is very nicely built, with a smooth focus movement. The auto aperture control worked fine on my Canon 5Ds and Panasonic Lumix S1R, where both accurately recorded aperture info in the EXIF data. If I had a note of caution, it would be to avoid dust and dirt getting into the lens barrel, given the long throw of the front elements.

No AF might be a concern for some, but for close-up and macro work I tend to use manual focus anyway. With the EOS RP and the Panasonic S1R, you’ve got very effective focus peaking available in manual focus mode, making things even simpler.

Images have -very- slight colour fringing at the highest of resolution, but nothing that can’t easily be eliminated during RAW processing. It’s only when I tried some other test shots with lenses at 100mm I realised just what a good job the lens designers at Venus have done in reducing colour fringing.

Compared to my older Canon TS-E90mm F2.8 which I often use for macro and close-up work, the 100/2.8 is sharper and with much better contrast. The lens quality is such that I can freely pick the aperture to use for depth of field reasons rather than stop down to improve lens performance.

Some time ago I tested the Laowa 60mm 2x macro and found it to be a good lens, but this one is even better

Given the relatively low cost ($449 on the Laowa site) of the Laowa lens compared to other similar macro lenses, it’s definitely worth considering.

For lens ordering/info see Venus Lens

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