Oly 45mm 1.8 vs Sigma 56mm 1.4

Started 2 months ago | Discussions thread
Doom Scythe Regular Member • Posts: 275
Re: Oly 45mm 1.8 vs Sigma 56mm 1.4

I have the 45mm f1.8 for 2 years now, and I just made an order for the 56mm a week ago. Will update once I received it.

Generally, am happy with the Oly 45mm but I find the focal length a bit too short for really tight portraits like headshots. There is a bit of noticeable distortion if I fill the frame with the subject.

I did some research online and there were quite a bit of discussion on best focal length for portraits, with 105-135mm equivalent being the most popular due to it being the shortest FL without noticeable distortion. I also looked at various comparison photos and agree with that conclusion.

Prior to this, I had always wonder why others preferred longer FL than 85mm equivalent for portraits, with some even going up to 200mm equivalent. Also, the aperture opening for the 56mm gives much better background separation due to larger aperture opening. Remember, amount of background blur (loosely speaking bokeh) is dependent on absolute aperture size, distance to subject and subject's distance to background. 56/1.4 = 40mm which is comparable to Olympus 75mm, 75/1.8 = 41.7mm. Compared to 45mm f1. 8 which only clock in at 45/1.8 = 25mm, the 56mm gives about 1.36 stops of 'extra blur' at the same 45mm FL, if that make sense. It is almost like shooting on a 45mm f1.1 if we are talking about background blur alone.

Don't get me wrong. I absolutely love the 45mm f1.8 as it is lightweight and unassuming. It is also sharp, and focuses well, though not blazingly fast in low light. But I believe the Sigma 56mm should be able to give that extra blur (1.4 stops worth), a little extra distortion reduction and just that little more reach for my street photography (yes, I know, but this is another topic altogether). All of this for a similar size to Pana 25mm f1.7, which I also think fits into the compact range. Only thing is it is 126g heavier, twice the weight. 😔

 Doom Scythe's gear list:Doom Scythe's gear list
Olympus E-PL7 Olympus E-M5 II Olympus M.Zuiko Digital ED 9-18mm F4.0-5.6 Olympus M.Zuiko Digital ED 40-150mm F4-5.6 R Olympus M.Zuiko Digital 45mm F1.8 +5 more
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