P900 with Achromats

 


Testing of the P900 with Three Achromat Closeup Lenses


In a previous section, as can be found here, I tested the Tokina 0.4D achromat on the P900 and I found that it gave good IQ and high magnification, with a field width of about 4cm at maximum zoom of 2000mm EFL and a working distance of about 2m.  That magnification is considerably higher than can be obtained with the P900 alone. Unfortunately that Tokina lens is no longer made and it is very scarce, so I tested some other achromat closeup lenses as possible alternatives.


I tested the Minolta No 0 (+0.94D, FL 1064mm, 55mm thread), the Canon 250D (+4D, 250mm FL, 58mm thread) and the Canon 500D (+2D, 500mm FL, 58mm thread).  I attached the closeup lens using appropriate step-down rings to the 67mm front thread of the P900 lens.  I used a similar setup to that used previously for testing of telemacro with the P900 as described here.


Minolta No 0 closeup lens

This lens gave a working distance of about 1.0m to 1.1m for the maximum zoom of 2000mm.  However, the IQ at max zoom was poor, with a “foggy” appearance.  The IQ was better at lower zoom settings, with the centre of the image being quite sharp, but there was some softness at the edges.  This was the case at all zoom settings.  A typical test image is shown below. (Click on the image for the full sized view.)



Above: P900 with Minolta achromat: 0.5s, f/5.6, 100 ISO, 650mm EFL, distance 1.0m


With the Minolta lens attached, the field width (magnification) was about 4cm at a zoom setting of 850mm EFL and about 11cm at 320mm EFL.


I concluded that although the lens gave a useful working distance and a good magnification range the poor IQ made it unsuitable for use with the P900.


I considered the possibility that I may have had a faulty example of the Minolta lens, which I bought used.  However, when I tested it on my FZ38 camera it gave images which were sharp right across to the edges.  It seemed that this lens was simply incompatible with the P900 zoom lens.



Canon 250D lens

I tested this lens over a range of distances and zoom setitings.  The lens gave a high magnification, with a field width of about 3.7cm at a distance of 0.25m at a zoom setting of 220mm EFL.  At a distance of 0.5m and a zoom setting of 105mm EFL the field width was 10.4cm.


Unfortunately, while images were mostly sharp in the centre, the edges were invariably soft.  Below are two typical examples. (Click on the image for the full sized view.)



Above: P900 with Canon 250D achromat: 1/25s, f/4.0, 100 ISO, 105mm EFL, distance 0.5m



Above: P900 with Canon 250D achromat: 1/5s, f/4.5, 100 ISO, 240mm EFL, distance 0.25m


I concluded that this lens was not suitable for use with the P900 due to the poor IQ.



Canon 500D lens

This lens gave a working range of about 0.5m to 0.6m, and good magniification over a wide range of zoom settings.  The IQ was also very good in all cases, being sharp across the entire image to the edges.  A typical example image is shown below.   (Click on the image for the full sized view.)



Above: P900 with Canon 500D achromat:  0.6s, f/5.0, 100 ISO, 320mm EFL, distance 0.54m


The field width at 0.5m was about 17cm at a zoom setting of 95mm EFL, 9cm at 185mm EFL, 6cm at 300mm EFL, 4.1cm at 400mm EFL, 2.8cm at 600mm EFL, 1.6cm at 1000mm EFL, and 1.25cm at 1400mm EFL.


As this lens gave good IQ and a wide range of magnification I concluded that it is a useful lens to use with the P900 even though the working distance is perhaps somewhat shorter than would be ideal.


Example images taken with the P900 plus 500D lens

Below are images of an orchid taken at a distance of 06m at different zoom settings.  The first image which was taken at 105mm EFL is similar in magnification to the image which would be obtained at the same distance without any closeup lens on the P900 at its maximum available zoom setting.  (Click on an image for the full sized view.)



Above: P900 with Canon 500D achromat:  1/8s, f/4.0, 100 ISO, 105mm EFL, distance 0.6m



Above: P900 with Canon 500D achromat:  1/8s, f/4.0, 100 ISO, 185mm EFL, distance 0.6m



Above: P900 with Canon 500D achromat:  0.3s, f/4.5, 100 ISO, 260mm EFL, distance 0.6m



Above: P900 with Canon 500D achromat:  0.5s, f/5.0, 100 ISO, 450mm EFL, distance 0.6m



Above: P900 with Canon 500D achromat:  0.6s, f/5.6, 100 ISO, 650mm EFL, distance 0.6m






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