Fred Miranda Offline Admin Upload & Sell: On
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TimWildAstro wrote:
After some more nights out and a bit of pixel peeping, the Sigma 14-24 DG DN is better at 14mm for astro than the Sony is in the 12-14mm range (with my copies at least). Taken with an A7Riv and viewed at 50%, both look superb. Zoom to 100% and the Sony exhibits slight stretching on stars midframe if corner focused, and stretching in the corners if focused for midframe. With my Sigma at perfect focus, pretty much all stars are round corner to corner at 14mm (focus accuracy is absolutely critical though, but the Sigma is easier than the Sony there too).
The above is mainly relevant if you're using a tracker though; if you're doing untracked images with slight trailing, then the tighter stars from the Sigma are no longer as beneficial. At 14mm, the Sony has slightly less vignette, and seems to have very slightly better light transmission. For tracked astro, the Sigma is slightly better than the Sony at the wide end....Show more →
With the optimal copies I tested, the Sigma 14-24 does perform slightly better at 14mm wide open, so I don't blame you from preferring it for astro.
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