17-70mm lens (Pentax or Tamron advice please)

Started 4 months ago | Discussions thread
MarcosBaez Junior Member • Posts: 31
Re: Proof is in your pudding

Hythloday wrote:

Massao wrote:

Are you saying DA 17-70mm is not good for aperture below f/8? If so, we agree:-D

Some 14 years ago I tested the DA16-45mm qnd the Sigma 17-70mm, see:

Pentax 16-45mm vs Sigma 17-70mm: Pentax SLR Talk Forum: Digital Photography Review (dpreview.com)

The best aperture is 8. The Pentax DA16-45mm is slightly less good below that aperture, whereas the Sigma 17-70mm is really horrible, at the WA end. This is conformed by the DXOMARK test.

The Pentax DA117-70mm performs slightly better than the Pentax DA16-45mm.

The Sigma lens that you mention is an older model than the one we are talking about: the Contemporary. The Contemporary is only 7 years old.

From dpreview:


Check the conclusion from opticallimits:


The Sigma AF 17-70mm f/2.8-4 DC HSM OS | C delivers very solid performance, with very good to excellent resolution in the image center and very good border and corner resolution and most focal length and aperture settings. The only exception are somewhat soft borders and corners at the shortest focal length with large aperture settings.

Like many standard zooms, the lens shows quite pronounced barrel distortion at the widest zoom setting, but only moderate pincushion distortion at the upper end of the zoom range. Vignetting is a bit pronounced especially at the shortest focal length and large apertures, but is no longer an issue when stopped down. CAs are well controlled.

The build quality is on a high level for a consumer zoom. Thanks to HSM, the AF is reasonably fast and nearly silent. It's a little disappointing though that focus ring rotates during AF operation.

Compared to its predecessor, the lens delivers improved performance in terms of sharpness, and comes in a slightly smaller and no doubt better looking package.

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