Why is performance wide open important?

[Pontus]

It is well known that most lenses perform best stopped down a bit, even a stop can make a big difference. Many people compare the IQ of lenses wide open even if the maximum aperture is different. I have never understood why, I mean shouldn't the faster lens be stopped down at least to the same aperture as the maximum aperture of the slower lens. A lot of times lenses were engineered fast only to give a bright viewfinder image, not to actually be used wide open. But this morning I thought of something. The bokeh is often best wide open because the highlights are absolutely circular since the aperture blades don't affect the image. Is this why wide open performance is so important to many people? Other reasons that I can think of is that one wishes to take advantage of the maximum light gathering possibilities of the lens (but this is not really a good reason if there are other faster alternatives available which can be stopped down a bit for better performance) and another situation when wide open performance is important is if the aperture mechanism is broken and only wide open shooting is possible. Most of the time I think it is a psychological issue. If we have paid money for a fast lens we wish to use it at it's limits. But maybe we should just accept that the limit is one stop down or so. People who only shoot wide open really miss out on a lot of lenses which could actually be better stopped down to the maximum aperture of a slower lens which happens to be a good performer wide open.

[kuuan]

as I see it you listed most reasons already, namely brighter viewfinder and better light gathering possibility. However the brighter viewfinder is not an issue with mirrorless cameras and the ever improving high ISO performance of modern cameras make the second advantage less important.
and then of course there is the smaller dof / stronger subject separation that may be desired!
it's these and the chance is that a f1.4 lens @f2 is sharper across the frame than a f2 lens.
because circular oof highlights may look favourable compared to cornered ones, in contrary in many cases I prefer the slower lens because of the deeper dof it gives wide open ( resp. I prefer lenses with many aperture blades because I can stop them down without the oof highlights to become cornered )

as for tests, imo it makes sense to focus on the wide open performance. If somebody forges out the additional money for a faster lens he will want to know wide open performance and also use it wide open. However better it also be compared to slower lenses at shared apertures.

curious to hear more from more experienced photographers!

[Pontus]

Yes, the reasons for wanting a faster lens are quite obvious, let's list reasons for and against fast lenses again:
+ better light gathering possibility (only marginal importance as sensors evelve)
+ brighter viewfinder (does not apply to mirrorless)
+ quite often speed correlates with quality as faster lenses are more expensive, no expenses spared.
- price
- size
+- shorter or longer DOF at maximum aperture (at smoothest bokeh if you will) depends on the effect the photographer is after. Can be both positive and negative.

But what amazes me is that there can be a lens which is the best in the world stopped down to f2 but some photographers won't buy that lens because they only shoot wide open. They would rather buy the best f2 lens just because it can be used wide open at f2, which the first lens (with fantastic IQ) can't since it is stopped down. This doesn't make any sense to me.

[kuuan]

[Pontus]

Yes, if these are important considerations. And I understand the OOF highlights issue. But many people categorically say that they only ever shoot wide open. These people miss out on a lot of lenses because many wonderful lenses are bad wide open but get wonderful stopped down.

[kuuan]

[Pontus]

A good example is the Minolta Rokkor 58/1.2 which many people use only wide open. This lens IS great wide open but it is even better @f2 wher the sharpness and contrast is much better, even the bokeh is better as it gets ultra smooth (as opposed to the somewhat busy bokeh wide open). But of course, this is highly subjective as some people use this lens for the very shallow DOF and the look it produces. But these "wide open people" never get to experience the lens at what I consider the optimal aperture which for me is f2.

[DigiChromeEd]

[kuuan]

[buerokratiehasser]

brighter viewfinder is often fool's gold since many rigs are not getting better after 2.8 or so

The whole issue seems too people-y to me, but maybe you can turn your argument around:

If I wouldn't need to shoot at 2.8 I would go for the 3.5 lens instead, which has been optimised for 3.5. (It may or may not be better than 2.8 stopped down, but physics work in its favour) Thus, performance at 2.8 is important. It's the USP of a fast lens.

[Lloydy]

I very rarely use a lens wide open, fast lens or not. The DoF is often too shallow for my taste in the final image, I like to see some detail in a picture. And generally the bokeh is at it's best one stop down, but again that's a matter of personal taste.
I think a lot of people use fast lenses wide open just because they enjoy the challenge of getting the result - the ultra shallow DoF and stylized bokeh - that is the signature of a particular lens. And that's OK if that's your style.

[anscochrome]

[tb_a]

[Pontus]

That is a good reason.

[tb_a]

[uhoh7]

Nearly every shot you see by HCB is at f/8.

What is not talked about, but varies to a great degree is f/11 performance. Equally critical to me as full aperture.

But we live in the age of fast glass, fuzzy noses and missed eyes.

[Attila]

[calvin83]

If you use a lens at WO, the performance at WO is important.

[Pontus]

True, sometimes we don't have a choice but most of the time we do. Why would you choose to only use a lens wide open?

[radissimo77]

Great discussion!

*I guess it makes a difference what aperture AND focal lenght we are talking about (f1.2 lens stopped down to f2? or f4?, if the lens is poor-there is no other option)

*In my photography it depends what I am shooting-e.g when I approach a subject I already know- yeah this will be f2.8 as you generally imagine your Depth of Field and shoot accordingly

* the wider open you are the higher ISO you can use and also shutter speed is in your favor to hand held the shot in some circumstances (as mentioned above not a huge issue with current modern cameras]

*the question is -if your eyesight and your camera [e.g magnification and peaking] actually allows you to focus ultra-shallow-DoF

*the more I shoot the more I stop down [when staring eith MF lenses all I wanted to shoot is WO!)

Cheers,
Rado

[tb_a]

[iangreenhalgh1]

The person who always says 'I only shoot wide open' is also the worst photographer I have seen.

There has to be a connection there.

No, I'm not saying who I'm talking about.

[Jeff Zen]

Why is performance wide open important?

Because the sun goes down, and I hate artificial light?

[mo]

You would have to approach this question on many levels,comparing those who are professional photographers and have been in the craft many many years (the lens is a tool ), to those who just love photography and are just hobbyists (the lens is a way of enjoyment a means to capture an image,something of a challenge to overcome).

There is a huge but subtle learning curve in photography, some find it easy and understand the theory and apply it accordingly, and some find out by reason of the use of a lens over a period of time.

So why shoot WO,to learn about the lens of course, what it does how it's best used.

I shoot a fast lens at WO to see what it can do, purely to "test" it out (I confess I do look at what is happening in the background,the blur of colours,the shapes and try to make it interesting,for me first then whoever elses looks at it ).

I have managed to pick up and use two fast lenses the Nikon SC 1.2/55 (now in Scotland) and the Canon FL 1.2/58 for reasonable prices. Why? because I wanted to see what the fuss is all about and to use a lens at 1.2.

What you are now discussing is where I am at,I find it better to stop down to F2 or F4 (slowly working my way through the F stops). If I had read this discussion before I bought my 1.2 lenses, would I have my current level of understanding...I don't think so. We have so much to learn when it comes to each and every lens we use. To have fun and enjoy,and learn something new is why I am here.

"The person who always says 'I only shoot wide open' is also the worst photographer I have seen."
Ian what do you mean by this? Surely there are talented wo photographers who are not bad,but have mastered that style.

[iangreenhalgh1]

I just meant that the person who most often and proudly proclaims to shoot exclusively WO is a bloody awful photographer and the best advert for not shooting WO.