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Ozzie_Traveller Oct 28, 2011 7:24 PM

Lens test comparisons - Sigma & Panasonic lenses & Panny FZ100
G'day all

Been some chatter on another thread about lenses & sharpness - I thought I'd post a bit more here as a dedicated thread, rather than hijacking someone else's thread about superzoom vs dSLR cameras

I've just had a bit of fun doing some side-by-side comparisons with our houseshold's variances of a
> a Panasonic FZ100 with 24x zoom [rated by panny as equivalent to 28 - 672mm in film camera terms]
> a Panasonic G2 with the panny 45-200 lens [equiv to 90-400mm] and
> a Pentax Kx with Sigma 28-300 [equiv to 42-450mm] and a 70-300APO [105-450mm]

The 'target' house is across the street - about 125metres [400feet] away;
all cameras were set to 12mpx - ISO-200 - WB-sunny - Exposure as "P" program, autofocus as 'centre-weighted'
Minor colour differences are visible, along with lots of image sharpness differences

1- here is the target house, lens at 300mm

2- Panasonic FZ100 vs Panny G2 vs Pentax Kx using a Sigma lens

3- Here's a 400pixel-peep from each of the above

4- Target house again, shot at 70mm

5- Corner sharpness this time - the Pentax with 2-sigma lenses & the FZ100

6- Centre sharpness [camera/lenses as above]

Apart from cropping & pasting onto a new canvas, no pp for sharpening etc has been done

Thoughts and comments always welcome
Regards, Phil

SIMON40 Oct 30, 2011 11:45 AM

Seems to be the Panasonic's processing that's the issue here- rather than the lens itself...!
Was the FZ100's sharpening at default..?
Maybe upload FZ100 images with different sharpness or compression settings...
Also drop to base iso- whatever that may be... :)

VTphotog Oct 30, 2011 7:01 PM

Some of the differences you are seeing are due to the different DOF characteristics of the various size sensors in the cameras. In the last set, corner sharpness can't be compared because the target is at an angle to the sensor plane, rather than perpendicular. Your FZ100 has much greater DOF, so the left and right sides of the photo, which are nearer and farther from the focal point, will look sharper than with the larger sensor Pentax. It does look like the 28-300 lens is considerably softer than the 70-300. I had a Tamron lens of that same range, which had a similar condition, but was able to cure it by adjusting the focus with the objective lens.
It might be worth re-shooting the test with a subject perpendicular to the camera. Would also be nice if we could see the Exif info.


BTW, "center weighted" refers to metering rather than focus. I assume you meant spot focus using central focus point.

Bynx Oct 30, 2011 8:54 PM

Ive got a Sigma 28-300 3.5 and its no where near as fuzzy as the images you posted here. But Im going to check this tomorrow when the sun comes up. I havent a clue about lenses and am using two lenses given to me on my D7000.

iowa_jim Oct 31, 2011 6:07 AM

I suspect that it would be best to use the 'native' or standard resolution for each camera. Reducing some of the camera's resolutions to match the weakest link will test the camera's software more than the IQ it is capable of.

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