Kit Lens Vs Manual Focus Prime lens
Sony's E mount 16-50mm F/3.5-5.6 PZ Lens that came as Kit in my NEX-5R today takes on the vintage Canon FD 28mm F/3.5 Chrome tipped Prime Lens. This wide angle lens, made for the full frame Canon SLR Cameras (with FD mount way back) becomes a 42mm Standard Lens on a APS-C sensor with 1.5X Crop factor. By far, this is my most preferred of lenses. I wanted to compare the performance in low light and this was the overall lighting conditions on a gloomy overcast day in Dec in Bengaluru with half the window drapes pulled back.
The above was shot with my Asus ZF5 (it does some heavy processing in low light loosing some details in wide angle shots). You could see the camera mounted on the Tripod and kept in front of the TV Stand. I've kept white A4 sheets to pep up the background. The lens was probably 2 feet away from the dancing girl figurine, which was the focused object. Due to lack of light, using the Canon, it was difficult to get focus peaking (simmering lights on Camera LCD as confirmation on focus). Managed to get a few blips on the crown. Camera focused in a jiffy using the Kit Lens though. Except Croping and Resizing, NO other Post Processing done. The main test shots are below:
The above is using Asus ZF5 (Flash came on, I don't know how to turn it off).
The above is the result with Sony Kit Lens at 28mm; F/4.5; ISO 100; 0.5sec.
The above is the result with The Canon 28mm Lens at F/3.5; ISO 100; 0.62sec. I don't know why the Cam should choose to keep longer shutter speed, inspite of getting more light from the 3.5 aperture.
In Pattern Metering and Camera set to Manual Mode, I got to adjust only the Exposure Bias (to make it zero) and shutter speed is chosen by camera. The
Canon Lens results in brighter Pics due to the 20% longer exposure time. Bokeh also is better compared to the Sony. Let us see crops from the Pictures. The
first is from Sony and
2nd is from Canon FD.
When I put the pen (for comparison), I could have disturbed the parrot figurine.
Focus was on the Crown (with Canon) and on the face with the Kit. Just touch the screen and focusing is done
.
The brighter Prime Lens brings out bit more details and result looks more pleasing.
The purple and Dark Green bird figurines are separated by about 55-65mm only. You can compare the Bokeh between the lenses.
The choco brown colour thing you see is the MDF board the TV stand is made of.
NOTE: Only in these above two Pics, "Auto levelling" was done to bring the dark colour to life.
The Pic below is a crop from Asus ZF5. Look at the Colors produced by the mobile Cam's tiny Sensor
. Though it has hell lot of noise, when seen by the side of a Pic from a APS-C Mirrorless, one can understand how much the signal processing technology has improved over the years.
Conclusions: The modern Era Kit lens (sold for Rs.15K separately) does admirably well when it comes to Resolution, Micro-contrast and Colour Reproduction. It looses out to the Prime (expectedly) in the Sharpness and Bokeh Dept. One can expect decent performance from it.
DON'T expect
MIRACLES from Kit Lenses
ALL the Times. AND, do NOT go to Pixel level with smaller sensors and even with bigger sensors when the light is low. See the 2nd Pic (from ZF5) in this post? Stop at THAT size or a little bigger when viewing on monitor.