Summicron - R 50mm f2 sweet spot

[leica dream]

Advertisement (gone after registration)

While researching various topics to improve my technique  I have come across the term "lens sweet spot", but just as a statement without explanation.

Using my Summicron 50mm f2 lens on my Leica R3 is this factor something which might influence my shooting.  I recall the comment was coupled in some way with a remark to "shoot wide" for improved results but surely that would lessen depth of field.  I need to understand the technique in simple terms.

[a.noctilux]

In my use ...

sweet spot for this lens and so many other lenses is f/5.6.

dof is enough and with film the shutter speed is fast enough in most situation.

With bonus, if we study the "qualitywise" it's f/5.6 that this lens is the most resolving/contrasting, if that matters.

 

[dpitt]

3 hours ago, leica dream said:

While researching various topics to improve my technique  I have come across the term "lens sweet spot", but just as a statement without explanation.

Using my Summicron 50mm f2 lens on my Leica R3 is this factor something which might influence my shooting.  I recall the comment was coupled in some way with a remark to "shoot wide" for improved results but surely that would lessen depth of field.  I need to understand the technique in simple terms.

I think the term sweet spot is more applicable to zoom lenses. They have a FL range where the performance is optimal.

Prime lenses have an optimal aperture range as mentioned above, and also they have optimal focus distance. Some lenses are better at close range (most macro lenses) and others are best at infinity. Best example I know is the F3.4 180mm APO-Teleyt R. Its military version was designed for long range aircraft identification.

You do not have to worry about the Summicron 50mm. It is an excellent performer at all distances IMO.

Summicron's are designed to be used wide open. The decision for a given aperture is more artistic than technical, if anything. I rarely stop them down if the DOF is large enough. F2.0 is very good and F2.8 is almost optimal performance.

Edited November 23, 2023 by dpitt

[leica dream]

Thank you both. It is so valuable for us real, real, amateurs to have such a wonderful resource as this forum for advice.  Going back to film after so many years is so stimulating and makes each shot a learning curve.

[earleygallery]

As above, the term is usually used to refer to the 'best' optical performance which will nearly always be stopped down to f5.6/f8 on a prime lens. A zoom lens will probably have some distortion at the ends of its range so may have a 'sweet spot' somewhere in the middle, but of course if that was a concern you wouldn't be using a zoom.

However photography is a personal subject IMHO and, for example, a Summar lens (on my Leica lllf) at f2 is the sweet spot for me.

The Summicron 50 R as said is an excellent lens and you don't really need to worry about anything other than how you prefer to use it.

[davidmknoble]

@leica dream, glad you asked the question!

As you are learning more about lenses, many Leica lenses have f/stops that have the highest combination of contrast while also sharpening up the corners.  If you are guessing, 2 f/stops in from wide-open typically hits that.  Some older R lenses it is 3 f/stops from wide.  The summicron is a unique lens that works great at 2- and 3- (f/2, f/2.8, f/4.0) and (f/2, f/2.8, f/4.0, f/5.6).

If the lens is an APO lens, like the Leica R APO 90mm Summicron, then you can bet all f/stops are really good.  

In the zooms, many Leica zooms have the highest overall contrast on the largest part of the frame near the middle range of the zoom.  Leica just seems to have done this so that the wider end and the uppermost end are really good, but the middle is great.  I love many of their zooms.

Enjoy!