Cautionary Measure When Purchasing A Used Sigma Art Or Tamron G2 Lens
Recently we had a customer drop into the studio with a Sigma Art Series 24-70mm F2.8, coupled to their Nikon D850. The reason for the visit was that the customer was unable to obtain sharp images and they asked us to check the combo and if we found that it needed calibration, to undertake this accordingly (we offer a free health check facility, so customers can gauge what needs doing before paying). They had purchased the lens as a used item.
Upon attaching the Sigma USB dock to the lens and opening the interface software, we were surprised to find that settings had already been applied to the lens. They had stated they had not entered any settings and had purchased the lens as a used item. The settings were cleared and the lens was re-calibrated using Reikan’s Focal software, the results being completely different from those that had been previously entered into the lens.
In this case, not only where the original values widely different from the re-calibrated values, they were for a completely different camera! (Note calibration values using Sigma / Tamron lenses that can be calibrated via a dock are specific to the camera in use and are rarely, if ever, universal). For a complete list of Sigma and Tamron lenses that can be calibrated please visit the respective manufacturer’s web-sites, as they are too numerous to list here.
The moral of the story, if you are purchasing a used Sigma or Tamron lens that can be calibrated at different focal lengths, using a USB dock, is to ensure that any previous calibration values have been cleared before using it on your camera.
In an ideal world, the previous owner should have cleared them before selling the lens. It can also be argued that the lens and any settings, should have been checked and reset by the used retailer, as part of their inspection process. In this case, the lens was purchased from one of the largest online used photographic dealers. However, it does demonstrate that these issues slip under the radar and that when you buy used equipment, you need to do your research and also check that previously embedded settings are reset - don’t assume that the seller (private or business) has done it, or even knows how to.