FZ38 Resolution (part 2)


Testing of FZ35/38 Resolution with ISO Setting

The previous section examined the resolution of the FZ38 at a constant ISO setting of 100.   I carried out further tests on my FZ38 to see how the resolution varied with different ISO settings.  For these tests I used the same resolution chart board that I used in the previous section, except that I added two areas near the chartboard centre that I printed from parts of a Fujifilm Test Chart kindly provided to me by Dr J. C. (Jimmy) Brown.

For my tests I added an area from the Fujifilm chart which provided a scale of uniform grey tones, and an area of a colour image of the fuselage of a plane, which included uniform areas of different colours as well as some fine details and black lines and edges.  These added areas were used to examine other aspects of IQ apart from the resolution readings of the coloured Es and black narrowing lines resolution charts. 

Jimmy had used the Fujifilm chart to compare images taken with his FZ50 using JPG and RAW, as posted on the DPR Panasonic Forum: http://forums.dpreview.com/forums/read.asp?forum=1033&message=37716047.

These tests showed that it was not possible to improve the measured resolution of the black and white resolution grid lines using RAW processing.  However, the tests did reveal that other aspects of IQ could be improved by using RAW with the FZ50.

The FZ50 uses the Venus III JPG processing engine, while the FZ28 uses the improved Venus IV engine, and the FZ35/38 uses a further improved JPG engine called Venus HD.  While using RAW has been shown to be beneficial for the FZ50, people have reported that for the FZ35/38 there is hardly any benefit in using RAW compared with just simply using JPG.  I always use JPG with my FZ35/38 as I am of the opinion that any advantages of using RAW are far outweighed by the disadvantages.  A RAW image file is very large compared with a fine JPG file and they take more time to record as well as occupying more space on the SD card and computer. The processing of RAW files is also time consuming and rather complex.  Since there is little to be gained I prefer not to record in RAW but I do usually carry out some PP (post-processing) on my JPG images and for that I generally use PSE (Photoshop Elements for Mac).

In relation to file size when using JPGs on the FZs, I carried out some tests on my FZ38 using different JPG compression settings and shooting modes.  The results showed that the actual compression used by the cam processing can vary.  Further details are given here.

Test Procedure

Using a tripod indoors under constant lighting, I set the FZ38 at a mid-range zoom setting that gave a FL of 176mm equivalent.  I adjusted the distance of the tripod from the chart board by small amounts until the 75mm line on the chart covered 400 pixels on the sensor (as in my previous tests) so that the size of the coloured Es in the chart image corresponded with the chart readings in pixels/mm.  From exposure bracketing I found that the optimum exposure was +1EV.   I used the 2 sec timer, A mode, and aperture f/4.0 throughout.  I took replicate shots at ISO settings from 100 to 1600.


Below are 100% crops taken from the centres of the images for 100-1600 ISO (without any PP) showing the coloured Es chart, the narrowing B&W lines chart, the scale of greys, and the plane fuselage (click on the image to see the full sized version).

Centre 100% crop, 100 ISO

Centre 100% crop, 200 ISO

Centre 100% crop, 400 ISO

Centre 100% crop, 800 ISO

Centre 100% crop, 1600 ISO

Below are the entire images for 100, 400 and 1600 ISO, reduced to 1000 x 750 pixels (click on an image for the larger version).

Full image at 100 ISO

Full image at 400 ISO

Full image at 1600 ISO

Continue to Image Comparisons and Discussion

Return to FZ35/38 Resolution Testing Part 1