90mm f2.8 vs. 85mm f1.8

[SirJackdeFuzzIII]

First post here / new guy.
Will try and keep it as short as possible. (please bear with me)
Been shooting since 1996, with Nikon gear. Current camera, D800.

I am pulling the trigger on a heavily discounted A7III (brand new).
I am not switching 100% to Sony, but i am adding Sony to my Nikon arsenal.
Currently, i can only afford ONE lens with the A7III.

I am looking into (for portraiture) the Sigma 90mm f2.8. (min focus distance, 50cm)
But, i can get the Sony 85mm f.1.8 for the same price. (min focus distance, 80cm)

Is there an advantage of getting the Sony 85mil, over the Sigma 90mil ?
Does anyone have experience with both ?

ALL info will be greatly appreciated.

Edited November 30, 2021 by SirJackdeFuzzIII

[SirJackdeFuzzIII]

This is the spec sheet :

https://cameradecision.com/lenses/compare/Sigma-90mm-F2.8-DG-DN-C-FE-Mount-vs-Sony-FE-85mm-F1.8

 . . . but is there something more that i should know ? 

[Pieter]

5 hours ago, SirJackdeFuzzIII said:

Is there an advantage of getting the Sony 85mil, over the Sigma 90mil ?

The main advantage obviously is the 1.3 stops faster aperture. For portraiture this will help you to get better subject separation. I wouldn't care much about the minimum focus distance as both 0.5 and 0.8 m are too close for portraiture with this focal length, unless you like that cropped chin close up look a la Sergio Leone.

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

[SirJackdeFuzzIII]

21 hours ago, Pieter said:

The main advantage obviously is the 1.3 stops faster aperture. For portraiture this will help you to get better subject separation. I wouldn't care much about the minimum focus distance as both 0.5 and 0.8 m are too close for portraiture with this focal length, unless you like that cropped chin close up look a la Sergio Leone.

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

Thank you very much Pieter !

Are you perhaps from South Africa ?

Would you know if you loose any 'functions' with the 3rd party Sigma lens, as apposed to the 'native' Sony lens ?

[SirJackdeFuzzIII]

PS : yes, i tend to do my fair share of very close up head shots.

[Pieter]

You'll not really loose anything except the focus hold button and AF/MF switch on the Sony (but you gain an aperture ring). Most 3rd party lenses don't allow 20/30 FPS capture rate on the A9 and A1 cameras, but this is irrelevant to you with an A7III.

I'm from the Netherlands by the way, so I understand your thought that I might be from South Africa.

Edited December 1, 2021 by Pieter

[SirJackdeFuzzIII]

11 hours ago, Pieter said:

You'll not really loose anything except the focus hold button and AF/MF switch on the Sony (but you gain an aperture ring). Most 3rd party lenses don't allow 20/30 FPS capture rate on the A9 and A1 cameras, but this is irrelevant to you with an A7III.

I'm from the Netherlands by the way, so I understand your thought that I might be from South Africa.

Thank you very much for the useful info Pieter.
Much Appreciated mate

[SirJackdeFuzzIII]

Hey Pieter, before i forget.
Is there any youtube channel that you can recommend to follow, regarding Sony and Sony related gear ?
Much Appreciated.

[Pieter]

I usually read written reviews, such as those from LensTip and from Marc Alhadeff at SonyAlpha.Blog. LensTip is very objective and factional with a lot of lab tests. Marc Alhadeff is more subjective with a lot of shots in the field. On YouTube I really like Dustin Abbotts channel. Though I dislike his smug personality and fake smiles, he more than makes up for it with his comprehensive and informative reviews, often with many comparisons to similarly specced products.

All three tested both the Sony 85mm f/1.8 and Sigma 90mm f/2.8. Seems I was mistaken about the AF/MF switch, both have one:

Sony FE 85 mm f/1.8 review - Introduction - LensTip.com
Sony FE85mm F1.8 for Sony E mount test/review on Sony Alpha Blog
https://www.youtube.com/watch?v=PkpbMoGQ9cM

Sigma C 90 mm f/2.8 DG DN review - Introduction - LensTip.com
Sigma 90mm F2.8 DG DN for Sony E mount test/review on Sony Alpha Blog
https://www.youtube.com/watch?v=4ocJdzkHdkE

From what I get from these reviews is:
 - The Sony is decent in the center (great when stopped down), but a bit softer in the corners
 - The Sigma is very sharp from center to corner
 - The Sigma has more vignetting and much more distortion (RAW) than the Sony

Distortion is a trade-off Sigma tends to make lately in favour of a compact lens with great sharpness. If you shoot a lot of RAW and don't have an automatic correction profile in your editing software, this is a pain. If you do have an automatic profile, this trade-off makes a lot of sense.

 

[SirJackdeFuzzIII]

GREAT info . . . thank you very much Pieter.
Looking into everything asap.