A7廣角紅移 bye bye! (再試#11 Dec17)

bubu

月前将部鷄肋A7交Alexty2師兄，改薄sensor前的IR filter，爲的是追求用wide angle時红移有所改善。
http://www.mclassic.com.hk/forum.php?mod=viewthread&tid=13707

首次看樣片，有點不理想，Alex熱心提議更換為更薄的0.3mm薄片。
昨天收機後夜回北京。今日醒來，竟然蓝天万里。立即用25mm和15mm粗試幾張，哈哈哈，不但北京冇霧霾，我部A7的红閘都99.9%不見了。贊!!!

至於四角成像有無顕著改善，我老花眼睇唔得出。反正我目標是红移，以後A7+15mm/25mm去旅行拍風光是OK的了。
成色方面，我感觉有輕微变化，好像天色有少許紫蓝。

Note: 有在Camera Raw修正Lens Vignetting，救到25mm。

bubu

VC 15mm 暗角難免。

kgv

吸引

M3fans

very nice ar!!

Jason

得喎！

redrede

又真係明顯改善咗

wesley

無紅，但係咪有綠邊呢?

C9.99

Thanks for info

dannytiong

難得 Alexty2 係一個好有熱誠同責任感既人.

edwardyung

藍得很

bubu

It seems to me my old version of Cosina 15mm is still hopeless on A7 even though the red shift has been largely dealt with.
That said, I am at least happy with the Cosina 25mm on A7 now.

So rarely in Beijing was today sunny and fog-free that I could further test the modified sensor with the 25mm.
I couldn't clearly see greenish edge, as Wesley mentioned, with today's set.
Yes, the blue is a bit plastic, as mentioned by Edwardyung. But I don't know if it's the lens or the modification.
On Photoshop, I didn't touch any color adjustment or white balance except Exposure, Fill Light and a little bit of Lens Vignetting. Didn't even increase Black.

Jason

The over-saturated blue sky probably is due to UV contamination. Maybe a UV/IR cut filter can help?

great pics, by the way!! esp like DSC06876.jpg!!

bubu

Jason 發表於 2015-12-18 00:28
The over-saturated blue sky probably is due to UV contamination. Maybe a UV/IR cut filter can help?
...

Dig from old files a shot by the same Cosina 15mm/4.5 lens on M8, equivalent almost to 25mm.
Look, the sky blue is so natural. Of course, the red shift, if any I doubt, was already cropped by the sensor.
I think I didn't use any UV/IR filter to avoid UV or IR contamination.
Now it proves to me, at least for this sample, M8's colour rendition suits my taste more than A7, modified or not, does.

What a memory.
It's time to get a M8 back, perhaps.

MYM8

Skkypole

I'm going to motify my A7 after seeing this thread. Nice shoots!
I got that "plastic blue" on my M9P + 35 pre A + polarize filter under a bright sunny day, but I still have no idea what coz that.

dailyjuice

rarely seen the blue sky in beijing !!

vincecharus

bubu 师兄，你建議我拿我的A7S去改嗎？

Jeansky

good news!!!!!!!!
但SENSOR 左邊好似有塵!!!!!!!!