EF 300 f/4 L IS sharpness....

^^Gord^^

^^Gord^^

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A question for EF 300 f/4 L IS owners, is there a noticable difference between f/4 and f/5.6 on your lens?

Any chance you can post a 100% crop?

Reading the reviews on the lens it has been suggested that the lens is sharp at f/4 and a slight improvement at f/5.6.

The copy I have at the moment seems to be softer at f/4 that I would expect.

I intend to give the lens a proper testing this weekend. The testing i've managed so far indoors with just ceiling lights isn't really a fair test but I would be interested in comparing the results from other lenses.

Cheers!
 
Will try and shoot some tests at the weekend with mine too, hand held or tripod mounted ?, IS on or off ?

Alan
 
It's worth remembering that the DOF at 3 metres (a guess at your indoor distance) with f/4 is only 10mm (near and far) whereas this doubles at f/5.6. The impression from your test would be that the shot was sharper as twice as much of the subject would appear to be in focus. Try shooting a point on the wall (2 dimensional image) and see if the results follow through.

I participated in a thread on another forum a couple of days ago where several people (me included) were reporting a better success rate with this lens on a crop body than an FF body...not your issue, but maybe highlights that the lens has a learning curve that needs to be revisited when one of the parameters changes.

Bob
 
Get outside and test it on the jets Gordon that will soon tell you generally a lens is always sharper stopped down a step or two but a lot of the lowfly guys as you know opted for your particular lens and they get good results and I would say given the weather where we go and the shutter speeds we need they are mostly shooting wide open.

Cheers
Bill
 
Indeed Bill. The reason I went for this lens was that it was a stop quicker than my 100-400 L IS. If I can't get good results wide open then I will have to reconsider my choice.
 
A friend of mine does lens reviews and puts them on his site. I can't access it from work at the moment but check out the lens review for the 300f4L IS there.

www.eos-images.com
 
EOS_JD said:
A friend of mine does lens reviews and puts them on his site. I can't access it from work at the moment but check out the lens review for the 300f4L IS there.

www.eos-images.com
Click to expand...

Thanks. Just read the review and noticed that the result did suggest a noticable difference between f/4 and f/5.6.

The difference seems more pronounced than what I see on my 100-400 L IS @ 300mm going from f/5.6 to f/8 but my test conditions were far from ideal.

I will test more over the weekend and get some 100% crops posted.
 
As suggested, most lenses are sharper as you stop them down a bit. I don't think you'll find any lens that doesn't.

Question is, how sharp is it wide open?
 
EOS_JD said:
As suggested, most lenses are sharper as you stop them down a bit. I don't think you'll find any lens that doesn't.

Question is, how sharp is it wide open?
Click to expand...

I did expect to see an improvement when stopping it down but it was a bigger improvement than I expected.

Wide open, it's showing worse result at f/4 than my 100-400 L IS does wide open (f/5.6) but I'll reserve judgement until I've test it in better conditions.
 
Below pics are unprocessed 100% centre crops from my 300 f/4 L IS, tripod mounted, mirror lockup, remote release and IS off.

f/4

300_f4_100_crop.jpg


f/5.6

300_f56_100_crop_001.jpg
 
Oooow...that doesn't look good. I think you need to try focussing on a test chart at 45 degrees. The increased DOF at 5.6 may be tricking you into thinking the focus point is good but in reality both shots have the same focus error.

Bob
 
Below pics are unprocessed 100% centre crops from my 300 f/4 L IS, tripod mounted, mirror lockup, remote release and IS off.
Click to expand...

hmmmm, I just can't buy that much difference. I mean obviously I can because it's there but I don't believe there is that much difference in a stop.

I'd make a small wager that the focus calibration is just a tad out on that lens. When you extend the DoF just a tiny bit it's masking the problem but at f4 and close focus, it's enough to give an OOF image.

It's possible that you might not even notice in the real world where you probably wont be focusing that closely. It's a an issue that needs sorting though and I'd reckon calibration would sort it.
 
Ah nuts! My original reply was lost in the forum software move, so repost......

Canon Bob said:
I think you need to try focussing on a test chart at 45 degrees.
Click to expand...

Thanks Bob. Can you point me in the direction of a good test chart?

dazzajl said:
hmmmm, I just can't buy that much difference. I mean obviously I can because it's there but I don't believe there is that much difference in a stop.
Click to expand...

Indeed!

dazzajl said:
I'd make a small wager that the focus calibration is just a tad out on that lens. When you extend the DoF just a tiny bit it's masking the problem but at f4 and close focus, it's enough to give an OOF image.

It's possible that you might not even notice in the real world where you probably wont be focusing that closely. It's a an issue that needs sorting though and I'd reckon calibration would sort it.
Click to expand...

I did consider focus and did try playing around with the settings but didn't get any improvement but I think you maybe right. I don't think I will catch any daylight today but will get out tomorrow to test it in the real world.

I may also try my 30D (no cross type AF at f/5.6) to see if that makes any difference.

Thanks everyone for your input.
 
Hey good luck with that Gordon hope you get it sorted before we hit the hills.

Cheers
Bill
 
A couple of 100% centre crops from unprocessed RAW files.

#1 30D, 100-400 L IS @ 300 f/5.6

100_400_f56_100_crop2.jpg


#2 40D, 300 f/4 L IS @ 300 f/4

300_f4_100_crop2.jpg


Looks a lot better outside, roll on the good weather so I can really test it on some fast movers.
 
Hello, here is a 100% crop from my 300 F/4 L IS. Shot at f/5:

Original (resized):
normal.jpg


100% crop:
100crop.jpg


Pretty sharp I think!

Tom
 
Hey Tom the second image really doesn't look particularly sharp on my screen.

Bill
 
explora56 said:
Hey Tom the second image really doesn't look particularly sharp on my screen.

Bill
Click to expand...

I'd agree but given the probable speed of the subject then it's unfair to expect better. A static object taken from a tripod mount would remove all the other variables.

Bob
 
Gordon maybe the best idea is to wait until we can get back outside and test it in action instead of worrying about it, won't be long now before the call of the Loop can be answered.

Meanwhile something to help ease the pain here is a little Tornado doing 550mph for you :-

forgord.jpg


Cheers
Bill
 
Yeah Bill. Not much more I can do now really. The shots from yesterday are pretty close so I feel better about the lens than when I did the indoor shots.

I don't think I'll see any low leveling until March but I may get a trip to Cottesmore this week if the weather holds out.

I need to get a Harrier this year, would you believe it's been 495 days since I last had one at low level!! Even worse when you consider how many visits I make to Cottesmore as my local base.
 
Yeh it will probably be end of Feb/March before I get down there you want a Harrier mate here you go....the lens will be fine I just got a Sigma 120-300 f2.8 itching to get outside with it but the weather is naff...the Harrier :-

harr1.jpg


Bill
 
Canon Bob said:
I'd agree but given the probable speed of the subject then it's unfair to expect better.

Bob
Click to expand...

Bob I hear what you say and yes fast action photgraphy is not easy, that's what we do it for, but I doubt you will find many fast action photographers worth their salt who will agree with your statement that it is unfair to expect their images to be tack sharp that is what these guys pride themselves in.

What about yourself Bob have you ever shot anything like this if so how did you get on ?

Bill
 
explora56 said:
Bob I hear what you say and yes fast action photgraphy is not easy, that's what we do it for, but I doubt you will find many fast action photographers worth their salt who will agree with your statement that it is unfair to expect their images to be tack sharp that is what these guys pride themselves in.

What about yourself Bob have you ever shot anything like this if so how did you get on ?

Bill
Click to expand...
Bill,
Sorry, I wasn't implying that it was unreasonable to expect better from the lens...far from it and sharpness can be obtained in these circumstances. My inference was that it was unfair to point to the lens being the issue as a high speed target like this has too many variables to pick out the lens as being the causal factor for a perceived softness. The lens will be equally sharp on a moving object or static object...the resolving power doesn't alter. Therefore an example promoting sharpness would be better qualified if the tog's limitations (or luck) were removed from the equation.

Bob
 
explora56 said:
Hey Tom the second image really doesn't look particularly sharp on my screen.

Bill
Click to expand...

I think given that it was taken with a 350d the sharpness of the shot isn't too bad. In answer to the original question, I have found no real difference as yet between the quality at F/4 and the quality at F/5.6.
 
ok guys,

as promised here are my test images taken of an alarm box on a nearby house, 100% crop from center of frame 200asa, Canon 1DmkII, 300mmf4'L' tripod mounted, mirror lock and remote shutter release, images straight out of camera just converted to JPEG, no ps work.

1st image is f4, second is f5.6, very little difference that I can see, as has already been said true tests are images shot in the field rather than static tests like these, I've been using the 300mm for almost a year now shot cars, motorbikes, planes, wildlife and macro with it and I've never been dissapointed with any of the images it produces at any aperture, it's a cracking lens and takes a 1.4x convertor beautifully.

Alan

f4ct.jpg


f56ct.jpg
 
Thanks Alan, much appreciated.

This is the sort of difference (i.e. very little) I expected to see. I think my indoor test was flawed. The comparison shot with my 100-400 L IS yesteday showed that.

Looking forward to getting to use the lens in anger.
 
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