Nex 7 + Sigma 70mm 1:2.8 DG Macro (pentax mount) - Printable Version +- Opticallimits (https://forum.opticallimits.com) +-- Forum: Forums (https://forum.opticallimits.com/forumdisplay.php?fid=4) +--- Forum: Sony (https://forum.opticallimits.com/forumdisplay.php?fid=14) +--- Thread: Nex 7 + Sigma 70mm 1:2.8 DG Macro (pentax mount) (/showthread.php?tid=2534)

Nex 7 + Sigma 70mm 1:2.8 DG Macro (pentax mount) - lfred - 03-26-2012 Photo taken wide open ( I can take picture at other F stop but the aperture ring control from the Chinese adapter does not allow for precise indication of the actual aperture) full size picture available if you click on the picture and chose "view full size" Nex 7 + Sigma 70mm 1:2.8 DG Macro (pentax mount) - lfred - 03-26-2012 an other one , same setting Nex 7 + Sigma 70mm 1:2.8 DG Macro (pentax mount) - Guest - 03-26-2012 Is that full frame and at infinity? I'm not an expert here but it seems pretty clean (maybe slight drop off in the corner esp the lower left) but not the ughly smearing that some of the wides produces. Nex 7 + Sigma 70mm 1:2.8 DG Macro (pentax mount) - Klaus - 03-26-2012 Yes, this is how it "should be" when using a high-performance full format lens on an APS-C body. Nex 7 + Sigma 70mm 1:2.8 DG Macro (pentax mount) - lfred - 03-26-2012 It was full frame but not infinity hence (I presume) the slight out of focus for the building at the infinity on the lower left second picture .. grr I just now realized that the adapter pass infinity... (any idea on how to fix that ?( does it need to be thiner or bigger?)) Nex 7 + Sigma 70mm 1:2.8 DG Macro (pentax mount) - Klaus - 03-26-2012 [quote name='lfred' timestamp='1332773688' post='17065'] It was full frame but not infinity hence (I presume) the slight out of focus for the building at the infinity on the lower left second picture .. grr I just now realized that the adapter pass infinity... (any idea on how to fix that ?( does it need to be thiner or bigger?)) [/quote] Well, you should actually be able to focus slightly beyond infinity in order to give some allowance e.g. for thermal expansion. However, if you cannot reach infinity the adapter is actually too long. This can't really be fixed. Nex 7 + Sigma 70mm 1:2.8 DG Macro (pentax mount) - lfred - 03-26-2012 Thank you, It's "ok" then as it goes beyong infinity. Focusing past a couple of meter up to the horizon will just require some focus rather than just a full ring turn.. Anyhow I'm glad that I can get sharp picture across the full frame.. Just need the right lens, would not mind a native E mount though.. Nex 7 + Sigma 70mm 1:2.8 DG Macro (pentax mount) - Klaus - 03-26-2012 [quote name='lfred' timestamp='1332782214' post='17068'] Thank you, It's "ok" then as it goes beyong infinity. Focusing past a couple of meter up to the horizon will just require some focus rather than just a full ring turn.. Anyhow I'm glad that I can get sharp picture across the full frame.. Just need the right lens, would not mind a native E mount though.. [/quote] Why don't you just use a magnified focus view ? Nex 7 + Sigma 70mm 1:2.8 DG Macro (pentax mount) - lfred - 03-26-2012 I do but still it's more convenient just to be able to use the infinity "position" to do brainless focus