Usually one of the first lenses that someone will buy after purchasing a DSLR is a prime lens, another common one would be a zoom lens to extend the distance of the standard kit lens.
The most common prime, and that which is growing in popularity is the 50mm, the nifty 50. Although really if you are using an APS-C camera, a 35mm may give you better scope, a 50mm is both cheap and versatile. Combine this with incredible quality at a low price and its an easy sale.
Like most camera manufacturers Sony has 2 50mm prime lenses; though Canon has the f1.2 which you have to pay a small fortune for, but is more specialist.
So what’s the difference, which one should you get? I’m not going to blind you with MTF charts, or talk technical figures, I’m going to give a hands on impression and show the types of shots I was able to pull off.
What’s the difference?
So why are their two lenses in the first place, why can’t there just be 1 lens such as the SAL50F14 which covers the lowest f-stop value of the SAL50F18. That would be great but its all down to cost.
Producing higher quality ‘fast’ glass with a lower f-stop value is usually more expensive, and when you combine it with differences in casing / construction there can be a hefty price difference. To put this into context the Canon f1.2 is about £900 more expensive than the f1.4
So the lenses target different people, and also different cameras.
The SAL50F18 is a cheap (in price) lens targeted to hobbists and is built from plastic with a plastic mount, the SAL50F14 is still plastic (but higher quality) and has a metal mount.
Also nice though not really required is that the SAL50F14 comes with a lens hood as standard.
The SAL50F18 can only be used by crop sensors (APS-C) but the SAL50F14 can be used by full frame as well.
The SAL50F18 uses a SSM style motor however the SAL50F14 still uses the internal screw drive system of the DSLR. They give around the same focusing speeds, however the screw drive is noticeably louder than the SSM and thus isn’t really suitable for recording movies. It would be nice if they would eventually update it with a SSM.
Both provide great image quality, however it can be seen that the F1.8 is soft fully open but improves as you step down. The F1.4 shows its 80’s inspired optics from the Minolta days, and is in need of updating for use in digital cameras of ever increasing resolution.
Having a low f-stop value helps increase bokeh due to the decreased depth of field, however it is not the end all of producing nice out of focus blur.
Overall Sony did a great job with the SAL50F18, its a great lens and produces some amazing sharp results. If you don’t require the lower light capibilities of F1.4 most people should stick with the F1.8.
If I were to have my dream lens, I would have the F1.8 in a metal body with focus window. Till then I’ll stick with the F1.4.