Ricoh GXR: Close-Up Lens Experiments (A16-24-85)

Introduction | Test Photos for Estimating the Magnification | Test Photos for Judging the Magnification Informally | Sample Photos

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This page presents the results of a quick-and-dirty investigation into close-up lenses on the Ricoh GXR with A16 24-85 camera unit, which does not have a macro setting. I also used close-up lenses (achromats) for more magnification. See what can be achieved.

Introduction

In my tests, I used the camera without any close-up lenses at a focal length of 85 mm equivalent (telephoto end of the lens). I used it also with a Marumi achromat with +5 diopters (which I use for my Leica X Vario), two stacked +5 Marumi achromats (+10), and a Dörr +10 achromat (from a slide copier) at this focal length. I was interested in how these lenses and combinations would fare on the Ricoh GXR A16 24-85. Luckily, the Dörr slide copier was delivered together with a 55 to 52 mm step-down ring (and other ones, too). So I was able to attach both achromats (52 mm) to the lens of the A16 24-85 camera unit.

Magnification

Again, I applied the formula from dkpeterborough (L-Camera-Forum) to calculate the magnifications for my close-up lenses:

Sensor width / object width = 23.6 [mm] / object width [mm] (The technical data for the A16 24-85 state a sensor width of 23.6 mm.)

The following calculations are based on test photos that I took to estimate the magnification for an equivalent focal length of 85 mm, which offers the largest magnification (see below):

No lens: 23.6 / 106 = 0.23
+5 diopters lens: 23.6 / 59 = 0.4 (Marumi +5 achromat)
+10 diopters lens: 23.6 / 43 = 0.55 (two stacked Marumi +5 achromats)
+10 diopters lens : 23.6 / 42 = 0.56 (Dörr +10 achromat)

The results are fairly similar to those achievable with the Leica X Vario at a focal length of 70 mm equivalent, although there are some slight inconsistencies...

Stacking Lenses

It seems to be possible to stack two lenses of higher quality without degrading image quality too much.

Vignetting

The lens of the GXR A16 24-85 camera unit shows already some slight vignetting even without a close-up lens.

I used the achromats with a 55-52 mm step-down ring that was provided with the Dörr achromat. In this configuration, the Marumi +5 achromat shows vignetting below 28 mm equiv. With two achromats, vignetting can be found below 50 mm equiv. The Dörr +10 achromat vignets already at 85 mm equiv. and is therefore more or less unusable in this configuration.

Quick Summary

With a +5 achromat, the close-up capabilities of the Ricoh GXR A16 24-85 macro lens can be extended without much effort to a magnification of about 0.4. A second stacked achromat achieves a magnification of about 0.55, which is below of what I would have expected. In my configuration, the Dörr +10 achromat shows vignetting even at 85 mm equiv. and is therefore of little use.

Test Photos for Estimating the Magnification

For all photos the distance was manually set to 25 cm and the camera moved to achieve optimal sharpness. Please do not take the results too seriously.

No close-up lens

Object size: 10.6 cm * 7.1 cm (0.23)

Marumi +5 achromat

Object size: 5.9 cm * 3.9 cm (0.4)

Marumi +5 achromats stacked (+10)

Object size: 4.3 cm * 2.9 cm (0.55)

Dörr +10 achromat

Object size: 4.2 cm * 2.8 cm (0.56)

Test Photos for Judging the Magnification Informally

The following static motifs are primarily meant to allow for judging the magnification differences between the conditions (1) no lens, (2) +5 diopters lens, (3) +10 diopters lens (= 2 +5 diopters lenses). As a close-up lens, I used two samples of the Marumi +5 achromat. Distance was set manually to 0.25 m (MF). I used full-screen magnification and mode 2 focus assist (gray contours) to aid manual focusing.

Click the images for larger versions.

No Lens	Marumi +5 Achromat	Two Marumi +5 Achromats (+10)

Sample Photos

Here are a sample photos taken under the following conditions: (1) no lens, (2) +5 diopters lens, (3) +10 diopters lens (= 2 +5 diopters lenses). As a close-up lens, I used two samples of the Marumi +5 achromat. Distance was set manually to 0.25 m (MF). I used full-screen magnification and mode 2 focus assist (gray contours) to aid manual focusing.