P900 and Telemacro

 


Telemacro with the P900


The P900 has a minimum distance of 5m (16.4ft) at which it will focus at its maximum zoom setting of 2000mm EFL.  This is considered by many people a rather long and sometimes inconvenient distance for taking shots of small sized subjects in enclosed spaces. (In comparison, the Panasonic FZ and TZ models generally have a miniimum focus distance of 1m to 2m at their maximum zoom setting.)  In another section, which can be found here, I tested the Tokina 0.4D achromat on my P900 and I found that it reduced the minimum focus distance at maximum zoom of 2000mm EFL to about 2m.


The P900 Manual says (on p40) to “Set the focus mode according to the distance to the subject” by selecting the flower symbol at the bottom of the multiselector dial.  The menu which is then displayed shows the choice of AF (normal autofocus) or macro close-up (the flower symbol).


The notes in the manual (p41) say to use AF mode when the distance to the subject is 50cm or more, or 5m or more at the maximum zoom position.  The manual says that when the flower symbol mode is used the P900 can focus as close as about 10cm from the subject.  There is no information given about the magnification values that can be obtained.

 

To investigate the focus modes in terms of magnification I carried out some tests using a tripod and with a ruler attached horizontally to a wall as the subject to determine the field width (magnification).  I also used a printed calendar card attached above the ruler to investigate changes in IQ.


I used a range of subject distances from 5m down to 5cm, measuring from the front of the lens housing on the camera.  At each distance, using the self-timer, I took shots at different zoom settings up to the maximum available zoom at each distance.  Since the P900 does not have a focal length indicator I read the actual FL from the image EXIF data.  As the zoom operates in distinct steps it was sometimes difficult to establish precisely the maximum zoom setting for a particular distance.  I therefore carried out some replication to reduce the scatter in the results, which are shown in the plots below.


AF Focus Mode

Below is a plot of the maximum available zoom setting in mm EFL versus subject distance using the AF mode.  I found that the AF mode operated normally at shorter distances than 50cm, in fact down to 5cm, which was the closest distance I tested.  (Click on the graph for a larger view.)


Above: P900 maximum available zoom setting versus subject distance


As can be seen, there is quite a steep decline in the maximum available zoom from 2000mm EFL as the distance becomes shorter, then the decline becomes less steep down to very close distances.


Below is a plot of the field width (maximum magnification) in cm at the maximum available zoom setting for each distance tested.  (Click on the graph for a larger view.)



Above: P900 image field width at maximum available zoom versus subject distance


As explained above, there is some scatter, particularly at the very short subject distances.  However, the “peak” in field width at a subject distance of 3m was quite repeatable.


At longer distances, the smallest field width of 11.6cm (greatest magnification) was obtained at 5m and 2000mm maximum zoom, with only slightly less magnification at 4.5m and maximm zoom of 1800mm EFL.  A field width of around 11.6cm was also obtained at a distance of 0.5m. 


At moderate distances, from about 1.5m to 4m, the magnification was actually less than at 4-5m or at distances closer than 0.5m.  At distances of 2.5m and 3.5m the field width was about 14.5cm and at 3m it was 15.6cm, the lowest magnfiication of all over the entire range.  Of course that doesn’t mean that the P900 can’t or shouldn’t be used at a distance of 3m.  It is just that in terms of telemacro the P900 gives the lowest magnification (largest field width) at 3m distance at the maximum available zoom at that distance, which is 850mm EFL.


At distances closer than 0.5m the magnification increased as the distance became shorter.  However, at closer than 0.5m, barrel distortion became evident and increased as the distance decreased, along with generally poorer IQ.


Macro Focus Mode

I found that AF mode and Macro mode gave the same magnification at a distance of 0.5m.  However, at shorter distances than that, using the macro mode allowed a higher maximum zoom setting at each distance, which resulted in a higher magnification than AF mode.  I found that for distances at and greater than 0.5m there was no difference between using either AF mode or macro mode.


Below is a plot of the results using AF focus mode compared with Macro focus mode at distances of 0.5m down to 5cm.    (Click on the image for a larger view.)



Macro Focus Mode and AF Focus Mode field width at maximum available zoom versus distance


As can be seen, the highest magnification over this range was at 5cm, where AF mode gave a field width of 7.1cm and macro mode gave 5.5cm.   As noted above however, at very close distances the IQ became poor.


From the results it appeared that to obtain a higher magnfication than a field width of about 11-12cm at a convenient distance and with good IQ it would be necessary to use an add-on closeup lens.  As described in the following section I have tested some achromat closeup lenses for that purpose.




Continue to Testing of the P900 with Achromats


Return to P900 Testing


Return to Home Page