Is it common not to shoot at wide open apreture even with a Prime Lens?


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ST_sg

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#1
I just realized why most of my pictures looks blur/soft is mainly due to those pictures were taken in wide open apreture ie. f/2.8 - f/4.0 even with prime lens. http://forums.clubsnap.org/showthread.php?t=101587
I thought that prime lenses should have better quality than zoom lenses.

Questions is, does it sound right to get a Fast Prime lens eg. f/1.8, f/2.8 and can't put in good use unless stop down to f/5.6 - f/8.0? :confused:

Or that's because "consumer" lens quality, unless go for 'L"? :dunno:

Any input from you guys and much appreciated if you can share your experience.

Thanks.
 

Astin

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#3
Rule of thumb:
Shoot at the aperture which is 2 stops down from the largest aperture.
Eg, if yr lens largest aperture is f2.8, then u should shoot at f5.6 or smaller to get a "sharp enough" image.
 

XXX Boy

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#4
It is common to shoot wide-open also. Esp when shooting in low-light conditions.
I have no prob with my 50mm Summicron and my 90mm Elmarit shooting wide-open.
 

ST_sg

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#5
Astin said:
Rule of thumb:
Shoot at the aperture which is 2 stops down from the largest aperture.
Eg, if yr lens largest aperture is f2.8, then u should shoot at f5.6 or smaller to get a "sharp enough" image.
Yes. I just did a quick tests with my 24mm f/2.8. Place my cam on table, self-timer took for a series of shots to a table calendar:
- ISO100 f/2.8, ISO200 f/2.8, ISO400 f/2.8, ISO800 f/2.8
- ISO100 f/4, ISO200 f/4, ISO400 f/4, ISO800 f/4
- ISO100 f/5.6, ISO200 f/5.6, ISO400 f/5.6, ISO800 f/5.6
- ISO100 f/8, ISO200 f/8, ISO400 f/8, ISO800 f/8

Agreed that, only f/5.6 and f/8 deliver better quality (center to corner).
That's why I create this thread to check with you all, seems like even prime lens I can't enjoy an "acceptable" quality at f/2.8 or f/1.8. Indeed what I need large aperture is because usually I take picture of my kids indoor (at living room, bed room) and I don't want flash yet at a decent handheld speed. ie. ~1/60s

I was quite fussy and see all the pictures at 100% view on screen are quite blur and keep thinking it could be my lousy cam-shake problem. :(
 

ST_sg

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#7
mpenza said:
I do shoot wide open with some of my lenses, primes or otherwise.
Is it sharp on screen at 100% view? Or usually you guys don't have such practise to view at 100% zoom? :think:
 

goering

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#8
What primes did you use? It would be better to post your shots.

I have the 24mm/2.8 and I do find it sharp enough at 2.8
 

sehsuan

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#9
replied your other thread; the cause is camera shake.

try different variations of holding or controlling your breath as you trip the shutter. you'll find one that works. a heavier camera may help to stabilize itself from being affected by camera shake.

i will shoot wide open using a wide angle lens when indoors only when i have certain requirements - like the ambient light is REALLY low, and i want to get a shot without using flash, yet reduce the chance for camera shake. that's for indoor shots using a wide lens. for indoor shooting with a long lens, it depends on what i want. i've tried out the 135/2 and 85/1.8 wide open before, the sharpness of the images is determined moreso by using an appropriate shutter speed.

outdoors, i use my 70-200 typically at f/3.2 to f/3.5, reason being i dont want the photos to have that shallow a DOF for my needs.
 

mpenza

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#10
ST_sg said:
Is it sharp on screen at 100% view? Or usually you guys don't have such practise to view at 100% zoom? :think:
find pics reasonably sharp. anyway, do you print your negatives at 10-12R in the past? if not, why are you so particular now ;p
 

mpenza

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#11
some unsharpened 100% crop samples shot wide-open from a 70-200 zoom. could still be sharper I guess but I was a bit tired after shooting for >1hour ;p


 

ST_sg

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#12
ok, here are my tests result just did before I started this thread...
all EF 24mm f/2.8 prime lens, ISO 100, Av priority, varies shutter speed, center focus point, under office lighting environment. shoot in raw, EOSviewer raw adjust +0.7 exposure compensation, auto WB.

f/2.8 center


f/4 center


f/5.6 center


f/8 center
 

ST_sg

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#13
top left corner f/2.8


top left corner f/4


top left corner f/5.6


top left corner f/8


Camera placed on table, I guess..there was no cam-shake, shot taken with self-timer. What do you think about the results? :think:

All input very much appreciated.
 

student

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#14
The question is: Is it common not to shoot wide open with a prime lens? The reason for the question is that your pictures were soft and you attributed it to possibly shooting wide open.

1 All lenses perform best at about two stops from its widest aperture
2 The reason for getting a prime lens (often with a wider aperture) is
(a) Faster speed at those time when the light is low, (2) brighter viewfinder, and (3) generally better performance (clarity etc) than zoom.

Problem with shooting at widest aperture: Depending on the focal lens, the depth of field is very narrow, and so you focussing is extremely critical. Eg with a 80 mm F1.4, the depth of field is very narrow. WHile the eyes may in focus, the ears are often not. So a slight unsteadiness can cause a soft image.

As far as you problem is concerned, most people overestimated their hand held ability, especially with subject like running toddlers and kids. I would rather be shooting at 1/250 instead of trying my luck at 1/60.

The problem is not with the lens. The problem is with improper use of the lens.
 

mpenza

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#15
pics actually look ok. go out and shoot more. worry less about "sharpness" at 100% viewing.

unless you want shallow depth of field or need fast shutter speed without using flash, shoot at a smaller aperture to get better results.
 

Prismatic

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#16
Basically, at wide-open, your picture will be soft, not blurred.
Shooting wide-open is quite common for people that dun have a choice, ie:low light and cannot use flash or simply wanting the shallow depth of field.
 

ST_sg

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#17
student said:
The question is: Is it common not to shoot wide open with a prime lens? The reason for the question is that your pictures were soft and you attributed it to possibly shooting wide open.

1 All lenses perform best at about two stops from its widest aperture
2 The reason for getting a prime lens (often with a wider aperture) is
(a) Faster speed at those time when the light is low, (2) brighter viewfinder, and (3) generally better performance (clarity etc) than zoom.

Problem with shooting at widest aperture: Depending on the focal lens, the depth of field is very narrow, and so you focussing is extremely critical. Eg with a 80 mm F1.4, the depth of field is very narrow. WHile the eyes may in focus, the ears are often not. So a slight unsteadiness can cause a soft image.

As far as you problem is concerned, most people overestimated their hand held ability, especially with subject like running toddlers and kids. I would rather be shooting at 1/250 instead of trying my luck at 1/60.

The problem is not with the lens. The problem is with improper use of the lens.
Thanks for your detail analysis. If need to get 1/250s and maintain smaller aperture, eg. f/5.6. I think a flash is a must for indoor lighting. Then set the 420EX to "fast page" and shoot at Manual-mode of 1/250s, f/5.6, ISO200.
Do you think I should be able to get a decent quality picture?

Btw, care to elaborate "improper use of the lens"? Does it mean I should use a better lens to shoot in such lighting environment?

Appreciate for all advises. :)
 

ST_sg

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#18
mpenza said:
pics actually look ok. go out and shoot more. worry less about "sharpness" at 100% viewing.

unless you want shallow depth of field or need fast shutter speed without using flash, shoot at a smaller aperture to get better results.
The main reason why I'm collecting prime/fast lens is because I need to shoot in low-light/normal indoor lighting condition without firing flash to my kids. And for easy setup also, not too cumbersome to put batteries to flashgun and mount it for use. I'd a 24-85 f-3.5-4.5 lens initially, results worst than now.

As the result, I picked up 50mm f/1.8 and 24mm f/2.8 (at my affordable spending). Nevertheless, the problem still persists though a bit better than where I started this 300D journey... :confused:

Any solutions from gurus here? :embrass:

Thanks much.
 

denniskee

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#19
Most, if not all lens (consumer or pro lens) are sharpest & brightest @ the centre than the corners, no lens makers can solve this because of physic law, mat'l property and tech. limitations.

Sharpness and light fall out also better as lens is stop down, no lens makers can solve this because of physic law.

Imagine (I just tried with my buddy's lens), hand hold 200mm f1.8, set @ f1.8.

Do you shoot @ 1/250 basic giude line? Mind you, the lens is 3kg, + camera is over 1kg without flash = slightly less than 5 kg.

DOV @ 5m is about 8mm. Imagine slightest hand shake.
 

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#20
is sharpness everything? i can accept a blur picture with great content but will trash a super sharp picture with no 'soul' substance or otherwise.

Just enjoy your hobby and shoot, i can accept all my lenses sharpess at their maximum aperture, be it 1.4 or 4, not so much of an issue is you are shooting kids, keeping a low shutter speed may have some blurness that will infact add to the kids playfulness and 'soul'. Dun be so uptight about sharpess, expend the energy on compostion and a strong image.

the softness on your f2.8 is fine really, i will only have a issue if it back/front focus.

one more thing about primes, the bokeh is quite nice (depending on which lenses) i like my 50mm f1.4 bokeh and love the 85mm f1.2 :lovegrin:, they help to create more interesting shots.
 

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