Sigma 28-300 f/3.5-f/6.3 and Pentax K-r

Started Jan 15, 2018 | Questions thread
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gaetanonline Regular Member • Posts: 106
Sigma 28-300 f/3.5-f/6.3 and Pentax K-r

Hi !

I recently bought this lens Sigma 28-300 just to have it with me in my next travels.

it's a second hand lens but in perfect conditions. At least it seems so.

Apertures should be f/3.5 and f/6.3 at maximum focal lenght ( 300 mm).

I recently noticed that, using my Pentax k-r, at maximum focal lenght it displays f/6.7

How is it possible?

It let me have f/5.6 till 150mm BUT over this focal lenght the only aperture is f/6.7 and I can't understand why if the lens shows that it can get f/6.3.

I tried the same with my other lens, a Sigma 18-200. Also in this lens apertures are f/3.5 and f/6.3 but it let me reach f/6.3 at 200mm focal lenght

so about the Sigma 28-300, is that an issue of the lens? Or does it happen because of camera and software of camera?

Hope that someone can explain me that.

Should I keep it or not ?



 gaetanonline's gear list:gaetanonline's gear list
Panasonic Lumix DMC-LX3 Olympus PEN E-PL1 Pentax K-r Olympus PEN E-PM1 Pentax K-50 +8 more
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Pentax K-r Sigma 18-300 F3.5-6.3 DC Macro OS | C
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