At the time of writing, I have had the use of a Marumi Achromat Close-up 330 (+3) supplementary lens for about a month for photographing insects in the field and, with practice, my close ups of insects are improving.

Male common blue damselfly with prey

Male common blue damselfly with prey, 18th July 2014 at Strinesdale Country Park, Oldham. Photographed with a Pentax K5 IIs plus 50-135mm DA* plus Marumi Achromat 330 (+3) screw in attachment. ISO 400, 123mm, f/13, 1/180sec.

Drone Fly, Uppermill 17 July 2014. ISO 320, 1/180 f/13, 135mm lens plus Marumi +3 attachment

Why use a close up supplementary lens?

The crème de la crème for photographing close-up and macro subjects is, of course, a dedicated macro lens that will offer magnification up to 1:1. I do possess a Pentax 35mm f/2.8 Limited Edition macro lens, which is tack sharp and photographs up to half life size (magnificaion 0.5x). In practice this is a great little lens for copying work, but the working distance is too close for insects, being just a couple of inches away from the subject at maximum magnification. Ideally, I needed to photograph insects from a greater working distance without having to go to the expense of buying a new macro lens. So, for now, I have a Marumi close-up attachment on loan from my father.

For anyone who wants to photograph small subjects just occasionally, the Marumi +3 attachment, complete with own sturdy case, is only 25mm deep and will fit into a small space in the camera bag.

About Marumi close-up lenses

I have always scorned the use of screw-in close up attachments since I used one in the past with very poor results. In fact there are still available plenty of sets of three close-up attachments (+1, +2, +4) from various manufacturers for about £20 for the set. These are of very variable quality and likely to produce inferior results including sharpness fall-off and chromatic aberrations (colour fringing problems).

However, achromatic lenses are designed to control the amount of chromatic and spherical aberration. Typically they are a close sandwich of two or three lenses with different properties that cancel out each others’ weaknesses. Consequently, the resulting image quality is much better than that of a simple lens…and, of course, they cost more. The Marumi DHG Achromat Macro 330 (+3) and  DHG Achromat Macro 200 (+5) attachments are screw-in achromatic supplementary lenses which attach to the filter thread of a lens (prime or zoom) in the same way as any other filter attachment. They are an affordable way to convert a short telephoto lens to a macro lens and are available in filter thread sizes from 49mm to 77mm. Whilst the manufacturer’s recommended price ranges from about £100-£200 at the time of writing (depending on filter size), in practice they can be bought for about half of that price if you shop around.

I am currently using a 72mm Marumi +3 lens on the 67mm filter thread of my Pentax 50-135 DA* lens, with the aid of a 67-72 mm step-up ring. You would preferably buy the same size as your lens filter size or, if using it on more than one lens, buy the larger filter size and an appropriate step-up ring to use the attachment on the lens with the smaller filter thread. I would not recommend buying a size smaller than your lens’s filter size (to use with step-down rings) as it will almost certainly cause unwanted vignetting of your images.

Below are shots of my camera with step-up ring and close-up attachment fitted.

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Pentax K5 IIs with 50-135 lens and Marumi +3 attachment mounted on a step-up ring

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Close up of the Marumi +3 on the K5 IIs taken with a Pentax 35mm macro lens on a Pentax K-7

Technical Note

Depth of Field (DOF) is critical when using any close up lens or attachment. The only things that determine DOF for a given sensor size are the aperture chosen and the magnification of the subject at the film plane. Therefore, whether you use a macro lens, prime or zoom lens, extension tubes or close up attachment, you still only need to consider the aperture and magnification. If you want to know more about this and about diffraction limitation, there are links in my previous article, Photographing Insects in the Garden.

Subject Magnification

The magnification that you require will be determined by the subject matter that you are photographing. For insects, a magnification from about 1:5 (0.2x), for larger butterflies, up to 1:1 (life size) for small insects, such as ants, would be ideal. The way to calculate what magnification you will achieve with the close-up attachment is to take the focal length of your lens and divide it by the focal length of your close-up attachment.

Examples:

For a 200 mm lens and Marumi Achromat 330 (+3)…(the 330 in the name is the focal length in mm of the attachment)…take 200 and divide it by 330:

200/330=0.6, so that combination will give 0.6x magnification of the subject at the sensor (film) plane. 

For a 135mm lens plus Marumi Achromat 330 (+3):

135/330=0.4, so that combination gives 0.4x magnification, just less than half life-size.

For 50mm lens and Marumi Achromat 330 (+3):

50/330=0.15 or the subject will be 15% of full size at the sensor plane.

The +5 attachment gives greater magnification throughout the range, but a closer working distance. With the +5 attachment and a 200 mm lens (the +5 attachment has a focal length of 200 mm), so:

200/200=1, so this gives a life size image. However, working with a life size image in the field is very difficult and depth of field problems make working at this magnification almost impossible in practice.

Using the lens/Marumi combination in practice

meadowbrown

Meadow brown butterfly on vetch, 18th July, Strinesdale Country Park, Photographed with a Pentax K5 IIs plus 50-135mm DA* plus Marumi Achromat 330 (+3) screw in attachment, ISO 400, 1/180 sec at f/13. Image magnification 0.35 at sensor plane, slightly cropped.

With my 50-135 zoom, I am using a crop frame camera with APS-C sensor and +3 supplementary lens. The close-up attachment gives a limited range in which focus on the subject can be achieved. It isn’t like using a macro lens, where focus can be achieved from infinity down to a few cm from the subject. It’s more like using extension tubes, so is more tricky in use than a macro lens.

First it is necessary to move to within focus range – this is easily found with experience. With the combination I am using, the focus distance is approaching 30cms from the end of the lens at the short end of the zoom range and a couple of cms less at the wide end of the zoom range. This does mean that it is necessary to approach the insects carefully and try not to create a shadow over them, which tends to make them fly off…but the working distance is generally quite comfortable.

The autofucus on my camera works quite well if within range otherwise it hunts horribly…as would be expected. An alternative method would be to focus the lens manually (set it to focus at infinity) then move in until the subject is sharp in the viewfinder…in years past, using a Tamron manual focus macro lens on a film camera, I used to set the focus in a similar way then move in on the subject.

Sharpness

This is not meant to be a learned article and is simply my observations of using the Marumi in practice. My impression, looking at my insect photographs, is that the quality is superb, but perhaps photographing a test chart will add some level of credibility to my opinion.

I wanted to look at sharpness fall-off across the frame, so I took a picture of a radial test chart. Below is the whole frame at the 50mm and the 135mm ends of the zoom lens, squashed down to 600 pixels wide. The chart was printed on ordinary office A4 paper on a laser printer, so quality is limited by that medium. However it shows no significant fall-off of sharpness across the frame at either end of the zoom range:

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Whole frame photographed with 50mm end of zoom and Marumi +3

Full frame photographed at 135mm end of a 50-135 lens with Marumi +3 attachment

Whole frame photographed at 135mm end of a 50-135 lens with Marumi +3 attachment

At the 135 end of the zoom range, I have also taken a 600 pixel crop out of the middle and edge of the frame:

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135mm end of zoom range, Marumi +3, centre of radial test chart, 600 pixels across at 1:1, showing sharpness in middle

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135mm end of zoom range, Marumi +3, edgeof radial test chart, 600 pixels across at 1:1, showing sharpness at edge. Note blue fringing…chromatic aberration is dealt with below.

Chromatic Aberration

I photographed a linear test chart, again printed on A4 office paper on an ordinary laser printer, to look for chromatic aberration on this particular lens/close-up attachment combination.

Here is the full width of the frame, squashed into 600 pixels wide for the web:

135mm end of zoom range, Marumi +3, full width of shot. Red edged area shown below enlarged.

If I just take the last 600 pixels on the right hand side of the frame (shown with border in red above) and display it here at 100%, it can be seen that there is a small mount of chromatic aberration (blue/yellow fringing) at the edge of the frame. (As would be expected, there is no colour fringing at the centre of the image)

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Chromatic aberration in sample shown 1:1 at the 135mm end of zoom range

This is easily removed in Lightroom:

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Chromatic aberration in sample, after automatic correction in Lightroom, shown 1:1

Conclusion

I was astonished at how good a supplementary lens could be. I am thoroughly enjoying the experience of photographing insects with the Marumi attachment and the results speak for themselves…very sharp images, good colour and contrast and only a little chromatic aberration, which is easily eliminated in post.

Typically, a 50-135 or 70-200 zoom lens with a Marumi +3 (330) close up attachment will be ideal for a variety of insects.

An advantage of using a supplementary lens over extension tubes, for example, is that it is not dependent on camera manufacturer or lens manufacturer…so long as you can match the filter size, it will fit any system and perform equally on any system. The qualities that it gives to the final image are the same with all camera/lens combinations but the overall quality of the image will also be dependent on the performance of the camera lens to which you attach it.

If I were to specialise in this type of close-up photography, I would want the convenience of continuous focus from infinity down to 0.5 or life size. However, I would not hesitate in recommending a Marumi Achromat +3 close up attachment for anyone who just wants to try out close-up photography, is working to a budget or wants to add a lightweight attachment to their kit rather than carry around an additional extra lens. I was not disappointed.

 

 

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