Are all lenses softer wide open?

[PhotoXopher]

EDIT
Samples here:
http://picasaweb.google.com/cwnauman/70200F28Samples#

Just curious (I really don't know), but is it normal for a lens to be softer wide open (f/2.8 in this case).

I'd post some samples but I really haven't had time to with Christmas and all. If possible I'll take some tonight on a tripod (only real fair way to do this).

Anyway, what would be a realistic expectation vs being too picky?

 

[Goontz]

Yes, I believe that any lens will tend to be sharper at f/8 than it will wide open. I suppose the exact difference in sharpness will vary, and it's probably more personal choice and what you view as acceptable. Looking at charts vs. real world will be hugely different as well.

 

[gsgary]

No Canon 300mmF2.8L is sharp

 

[DScience]

Yes, I believe that any lens will tend to be sharper at f/8 than it will wide open. I suppose the exact difference in sharpness will vary, and it's probably more personal choice and what you view as acceptable. Looking at charts vs. real world will be hugely different as well.

No no no no...Some lenses, I can't say what %, will be softer at it's widest aperture. However this is lens specific. There are GREAT lenses out there that perform very sharp at wide open apertures, just as sharp as other f stops.

However what you should keep in mind, is that when a lens is wide open it's DOF is a lot smaller, so I think a lot of times people think it's soft simply because much of the picture is soft and out of focus. But the focal point can still be tack sharp. As an example lens I would say look at the 85mm f/1.4. It is insanely sharp wide open at 1.4

 

[PhotoXopher]

I've found if I underexpose the f/2.8 shot by one stop it's better and actually more on par with the other f/stops exposure.

Samples here (for some reason Picasa doesn't work so well when posting photos on the forum) and my flickr account is maxed for the month:

All shot at 200mm on tripod in aperture priority mode. -.5 exposure compensation on the second to last one and -1 exposure compensation on the last one at f/2.8
Picasa Web Albums - cwnauman - 70-200 f2.8 S...

Full exif available by clicking 'more info' on the right hand panel.

After doing this the only real difference I see cycling through them is the depth of field... (other than 100% views).

Thanks for any input!

 

[chip]

Usually you get what you pay for. Cheap lenses are usually terrible wide open. Even expensive lenses may get a little softer wide open but still more than acceptable.

 

[PhotoXopher]

I guess that's why I'm asking... I don't have anything to compare it to.

 

[Shockey]

Yes lenses are softer wide open and get soft again on the other end starting generally at f14.
Having said that there are several Very Expensive lenses that are quite sharp wide open but even they are sharper a few stops into the range typically lenses are sharpest around f5.6 or f8.

Inexpensive lenses are typically quote soft wide open but two stops into the range they will be sharp.
If you have an f2.8 lens that is not sharp stop it down to F4 and it should be sharp by then, this is quite normal.

 

[PhotoXopher]

OK, I guess I kind of figured as much but wanted to make sure I wasn't beeing too picky.

 

[Goontz]

http://www.thephotoforum.com/forum/...to-gallery/186881-optimum-aperture-ratio.html

The question here isn't the same, but there's some helpful posts that are related.

 

[cliffy13]

The majority of lenses do get better as you stop them down but it does not apply to all lenses old and new,I have a 30 year old Vivitar 300mm f 5.6 that is as pin sharp wide open as it is at f11

 

[PhotoXopher]

Has anyone looked at the examples I posted?

Just wondering what the general concensus is of this particular example.

Thanks

 

[Derrel]

Has anyone looked at the examples I posted?

Just wondering what the general concensus is of this particular example.

Thanks

I looked at the eight pictures. The center sharpness and contrast looks remarkably similar in all the photos! Remarkably similar. The depth of field increase is visible through the range. What your test setup did not test was edge of field performance; I suspect that at f/2.8 the edges are somewhat fuzzier than the center, and stopping down to f/4, or f/4.5 or thereabouts, probably equalizes the performance across the entire field.

Some lenses are every sharp wide-open and are pretty close to optimized for wide-open shooting; the exotic super telephotos for example, can be bitingly sharp wide-open,and simply incredible stopped down as little as 1/3 to 1/2 of an f/stop; the 300/2.8 AFS-II and 200 f/2 VR~Nikkors spring to mind from my own experience. Some superteles,and other semi-exotic lenses are actually LESS-sharp as they are stopped down to small apertures like f/8 or f/11 and are MUCH sharper at wider apertures because the lenses are optimized for wider-aperture use.

Another issue now is diffraction due to high-density sensors. Very careful tests will show that the images at f/5.6 or f/6.3 or f/7.1 start to look LESS-sharp than those shot at wider apertures when you set up one camera and lens and shoot it from wide-open down to smaller f/stops. Each specific camera/sensor will have its "diffraction limited f/stop". At 12.2MP on a 1.5x sensor, that aperture is around f/5.6; smaller apertures, like f/8, deliver lower apparent sharpness results than photos shot at say, f/4.5 with a top-quality lens.

 

[o hey tyler]

The majority of lenses do get better as you stop them down but it does not apply to all lenses old and new,I have a 30 year old Vivitar 300mm f 5.6 that is as pin sharp wide open as it is at f11

There's a few stops between f/2.8 and f/5.6...

 

[PhotoXopher]

Thanks Derrel, I appreciate it... So in your opinion, do I have a good copy? I'm starting to think so after doing this test, and I learned something along the way that will help me tremendously when shooting... At f/2.9 I can set my exposure compenstation to -1 stop and get sharper, faster, photos with equal exposure to that of f/4 with no exposure compensation.

I hope that made sense