Up Close and Personal - when old meets new

For this post I thought I’d combine old and new to see how well old technology works when combined with a modern high megapixel camera like the Nikon Z7ii. The Nikon PB-6 bellows unit was released in 1983, 37 years before the introduction of the Z7ii, so I thought it would be interesting to see how the two can be used together.

Nikon's PB-6 is built like a tank. It is heavy and beautifully machined. While no longer being made, there are still plenty of near-mint condition PB-6 bellows available on the used market. The unit comprises two rigid metal standards connected by an accordion constructed from a leatherised fabric material giving a light tight tube between the lens and camera. These two standards are mounted on a geared rail, allowing the positions of the front (lens end) and rear (camera end) of the bellows to be independently positioned. By moving the two standards closer or further apart the extension of the bellows, and thereby the overall magnification of the system, can be varied seamlessly between 48mm and 208mm. The rail is marked with two scales to allow the extension to be accurately measured.

In order to use the bellows, the required magnification is chosen by moving the front and rear standards to a predetermined value, depending upon the lens being used. The system is then focused by moving the whole assembly relative to the subject. Technically the system can be focused by moving either the front or rear standard as well, but this will change the magnification and defeat the object of choosing the desired magnification in the first place. To assist with focusing, Nikon have used a double dovetail on the geared rail, with a base block that can manually drive the whole rail backwards and forwards.

Each of the geared controls can be locked into place to prevent unwanted movement or inadvertent adjustment during use.

***Nikon PB-6 Bellows in partially extended position***

Although just about any lens can be used on the bellows with the appropriate adapters, I chose to use a Nikon EL 50mm f/2.8 enlarger lens. This is fitted to the front of the bellows in a reversed orientation using a combination of a Nikon BR-2A reversing adapter ring and a 40.5 - 52mm step up ring. The step up ring screws onto the 40.5mm front filter threads of the EL 50mm lens and also onto the 52mm thread on the BR-2A. The BR-2A is also fitted with a Nikon f-mount bayonet that allows it to be connected to the f-mount socket on the front of the bellows.

At the rear of the bellows, the Nikon Z7ii is simply attached to the f-mount bayonet on the rear standard using the standard FTZ adapter. This provides sufficient clearance so that the camera can be attached to the bellows without fouling the rear standard foot or spacer rail (see below).

***Nikon PB-6 Bellows - fully extended with reversed Nikon EL 50mm f/2.8 Enlarger lens and Nikon Z7ii.***
The FTZ not only converts between the Z-mount on the camera and the F-mount on the bellows but also provides sufficient spacing so that the camera doesn’t make contact with the rear standard foot during mounting. This would also allow a gripped camera like the Z9 to be used

My subject was a Japanese Anemone (Eriocapitella hupehensis “September Charm”) flower from my garden. The flower was arranged in a vase on my desk. The diameter of the flower (petal edge to petal edge) was measured at 55mm.

The flower was first photographed using the Nikon Z7ii with a Nikkor Z MC 105 f2.8 VR macro lens at magnifications of 1:3 and 1:1 for comparison. I used the built in Focus Shift Shooting to collect the images for stacking. Stacking was performed using Helicon Focus software. The camera was set with a shutter speed of 1/10th second and aperture of f/16. The ISO selected by the camera was 500.

Following the initial stacks using the Nikkor macro lens the camera and bellows were set up on a tripod. I used the bellows on a Cognisys StackShot computerised macro rail controlled using Helicon Remote software to acquire the focus stacks. Two setups were used, one with the bellows set to the minimum bellows extension of 48mm (to achieve the minimum magnification ratio) and the second with the maximum bellows extension of 208mm to achieve the maximum magnification with this lens.

Note that the PB-6 bellows and StackShot rail add a substantial height to the set up (see below) resulting in having to reposition the camera to achieve as close as possible to the same image as the macro lens images. As such there will be variations in the images shown below, but they are sufficiently close to be able to draw some comparisons.

***Nikon Z7ii with PB-6 bellows and reversed Nikon EL 50mm f/2.8 enlarger lens mounted on Cognisys StackShot macro rail and set to view Japanese Anemone flower at maximum magnification***

The Nikon EL 50mm f/2.8 is not electronically coupled to the camera in any way so the system has to be set manually. For the minimum extension (48mm) image the shutter speed was 1/4th second at ISO 640 with the lens aperture manually set to f/8. In the case of the maximum extension (208mm) image the shutter speed was 1.3 seconds at ISO 640, again with the aperture manually set to f/8.

The increase in magnification due to the bellows extension is calculated as extension/focal length so with the bellows at 48mm this would give an increase in magnification of 48/50 or approximately 1x. The bare lens is reported to have a magnification of 0.5x when reversed so this will give an overall magnification of 1.5x. The effective aperture can be calculated as nominal aperture x (1 + magnification) giving a value of f/8 * 2.5 or f/20.

For the full extension of 208mm the additional magnification becomes 208/50 or 4.16, giving a total magnification of approximately 4.6x and an effective aperture of f/8 x 5.6 or f/45.

The images from the four scenarios are shown below.

***Nikon Z7ii with Nikkor Z MC 105mm f/2.8 VR set for magnification of 1:3, 1/15th second at f/16 (effective) and ISO 500***

***Nikon Z7ii with Nikkor Z MC 105mm f/2.8 VR set for magnification of 1:1, 1/15th second at f/16 (effective) and ISO 500***

Nikon Z7ii with Nikon PB-6 bellows set at minimum extension with Nikon EL 50mm f/2.8 enlarger lens
Magnification of 1.5:1, 1/4 second at f/8 (f/20 effective) and ISO 640

Nikon Z7ii with Nikon PB-6 bellows set at minimum extension with Nikon EL 50mm f/2.8 enlarger lens
Magnification of 4.6:1, 1.3 seconds at f/8 (f/45 effective) and ISO 640

In the two side by side images below I have compared the results from the PB-6 bellows to the Z-MC 105 f/2.8 VR lens cropped and resized/resampled in Adobe Photoshop to give approximately the same magnification image. Note the images are not identical due to slight differences in camera position between the macro lens and bellows setup. From the images, the zoomed Z MC 105mm image (below right) initially appears to have more contrast compared to the bellows version (below left) and smoother tones, but the stacking process has created smearing around the stamen. Zooming in using Lightroom shows the bellows image to have significantly more detail on the stamen and pollen without these stacking artefacts

Screenshot from Adobe Lightroom Classic showing the 1.5:1 magnification PB-6 image (left, select) compared to the cropped, resampled and zoomed image from the Z MC 105 f/2.8 VR macro lens (right, candidate).
Both images are shown zoomed in Lightroom’s compare window.. The image from the PB-6 (left) is clearly sharper and contains more fine detail than the Photoshop resampled version. The cropped image is still perfectly acceptable, however, when viewed at normal sizes

Repeating the comparison with the bellows set to maximum extension and the macro lens cropped and zoomed to give the same 4.6x “magnification” we can see that again the bellows image (below left) has more detail than the zoomed image from the macro lens (below right) when viewed in Lightroom (not as obvious on the web images below). Both images show smearing from the stacking process that may have been improved by using smaller step sizes, particularly in the case of the StackShot / bellows image. The ‘in focus” areas of the bellows image are significantly sharper than those of the rescaled macro lens.

Screenshot from Adobe Lightroom Classic showing the 4.6:1 magnification PB-6 image (left, select) compared to the cropped, resampled and zoomed image from the Z MC 105 f/2.8 VR macro lens (right, candidate).
Both images are shown in Lightroom’s compare window.. The image from the PB-6 is clearly sharpen and more natural looking than the Photoshop resampled version and shows significantly less noise / sampling artefacts.

Conclusions

High megapixel cameras and modern macro lenses can capture amazing results but many of these combinations are limited to 1:1 ratio or life-size without having to use specialist ultra macro lenses like the amazing Canon MP-E 65mm f/2.8 or the Laowa 25mm f/2.8 2.5-5x lenses. Zooming and resampling using Photoshop is a possible way to increase the effective magnification but, even by 1.5x, the Photoshop image is starting to lose out compared to the lens and bellows combination. At higher magnifications these differences become very marked.

The PB-6 bellows used for these images were purchased used from eBay for £80, Nikon EL-50mm f/2.8 enlarger lens for £45, 40.5 to 52mm stepping ring for £4 and Nikon BR-2A reversing ring for £18, giving a grand total of £147. This is a remarkable price for a lens system that is clearly capable of approaching 5x magnification and showing there is still a place for the veteran Nikon PB-6 bellows even with modern equipment.

In fact, I found the bellows to be much easier to use with the Z7ii than with my D850 DSLR. The viewfinder image was clear and bright even when using the PB-6 at its maximum extension, equivalent to an aperture of f/45. It was not possible to see enough through the D850 optical viewfinder to be able to set the focus stacking start and end points (live view was also quite dark to determine accurate focus), while the Z7ii electronic viewfinder was a joy to use.

I plan to repeat the testing with the PB-6 bellows, StackShot and Helicon Remote using smaller step sizes to see whether the images obtained can be improved further, but that is a job for another day.

In summary, I have been pleasantly surprised by how well the PB-6 bellows and a cheap enlarger lens work when mounted on a modern high resolution mirrorless camera like the Nikon Z7ii.

Up Close and Personal - when old meets new

Conclusions

More Photos using the PB-6 Bellows:

Auto Capture with the Nikon Z9

High ISO Noise Reduction Tests