#11 (permalink)  
Old 09-09-2009, 05:39 PM
kpy kpy is offline
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Default f value affects your depth of field and in-focus range

nice shots - except for the focus

ur f 2 and f 3.2 aperture settings options may very well be ur problem in this instance

maybe try pulling the f values back to increase ur depth of field and in-focus range

? which lens did u use? the canon 50m 1.8 ? or one of your zooms ?

yeah, as u say with the single subject maybe go for keeping the eyes in sharp focus, or the whole face is easier to start with

with the groups shots you will always need an even broader focus / depth of field zone - f 3.2 may not get u there

e.g. theres plenty of light so a much safer f value for u to try might be to start with f 4 to 5.6 for the one person shot, and even to start with an f 8 for the group shot, and experiment back from there

then guess u know like to set ur focus point on the face/eyes of the person closest to your camera

but I'd might steer clear of f 2, even for a single person shot - unless u have access to a really really good Canon lens e.g. 2.8 zoom, or something like the f 1.2 50 m, or f 2 100 m or similar lens - like even then some fixed length Canon lens will have a bunch of trouble and give inconsistent results around f 2, and may still be soft or hit and miss - even for the Canon 50 m 1.4 - even its notorious for being soft in parts around f 2 to f 2.8

Understand it is also possible for Canon lens to be checked and re-calibrated by Canon as well if they seem to be coming up a bit too soft

just some thoughts anyway
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Last edited by kpy; 09-09-2009 at 06:03 PM.
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  #12 (permalink)  
Old 09-09-2009, 07:25 PM
Elmo's Avatar
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It seems to me both images suffer from lens flair. That is the overall fog that help the image seem soft. To help reduce this do not use a u/v filter and do use a lens hood.
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  #13 (permalink)  
Old 09-10-2009, 12:33 AM
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Quote:
Originally Posted by kpy View Post
nice shots - except for the focus

ur f 2 and f 3.2 aperture settings options may very well be ur problem in this instance

maybe try pulling the f values back to increase ur depth of field and in-focus range

? which lens did u use? the canon 50m 1.8 ? or one of your zooms ?

yeah, as u say with the single subject maybe go for keeping the eyes in sharp focus, or the whole face is easier to start with

with the groups shots you will always need an even broader focus / depth of field zone - f 3.2 may not get u there

e.g. theres plenty of light so a much safer f value for u to try might be to start with f 4 to 5.6 for the one person shot, and even to start with an f 8 for the group shot, and experiment back from there

then guess u know like to set ur focus point on the face/eyes of the person closest to your camera

but I'd might steer clear of f 2, even for a single person shot - unless u have access to a really really good Canon lens e.g. 2.8 zoom, or something like the f 1.2 50 m, or f 2 100 m or similar lens - like even then some fixed length Canon lens will have a bunch of trouble and give inconsistent results around f 2, and may still be soft or hit and miss - even for the Canon 50 m 1.4 - even its notorious for being soft in parts around f 2 to f 2.8

Understand it is also possible for Canon lens to be checked and re-calibrated by Canon as well if they seem to be coming up a bit too soft

just some thoughts anyway
Thank you for the info. I was shooting with my Canon 50m f1.8. I was shooting at the f2 range to blur the background, but what you said makes since now. I will start by using f4 on single and f8 on groups. I wonder about my lens sometimes since it does seem to shoot soft. I have never had it re-calibrated I might have to look into that. Thank you so much for the help I really do appreciate it.

Quote:
Originally Posted by Elmo View Post
It seems to me both images suffer from lens flair. That is the overall fog that help the image seem soft. To help reduce this do not use a u/v filter and do use a lens hood.
Elmo, it looks like I need to get a lens hood. I wasn't using a polarized or uv filter for these since I don't have one to fit my 50m but I have used it on other lenses and they do appear soft sometimes too. I will be looking up a hood this weekend! Thank you!
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  #14 (permalink)  
Old 09-10-2009, 01:09 AM
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looks like a resolution issue.. are you saving full quality?
IE "11" on the photoshop quality slider?
(highest quality)
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  #15 (permalink)  
Old 09-10-2009, 01:16 AM
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Quote:
Originally Posted by candleman View Post
looks like a resolution issue.. are you saving full quality?
IE "11" on the photoshop quality slider?
(highest quality)
Well actually I was saving it at an 8. That might make a difference. But to me the picture looks fuzzy, noisey before I save it.
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  #16 (permalink)  
Old 09-10-2009, 01:46 AM
kpy kpy is offline
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Default Canon 50m f 1.8 lens review - great image quality when stopped down - best @ f 5.6 !?

Quote:
Originally Posted by photomom2008 View Post
Thank you for the info. I was shooting with my Canon 50m f1.8. I was shooting at the f2 range to blur the background, but what you said makes since now. I will start by using f4 on single and f8 on groups. I wonder about my lens sometimes since it does seem to shoot soft. I have never had it re-calibrated I might have to look into that. Thank you so much for the help I really do appreciate it. ....

yep, cheers, some reviews will state that many Canon fixed lens are a bit soft at those f values
u might find this dpreview.com lens review article on the Canon 50m f 1.8 II very helpful
its a nice little lens, and excellent value
u just need to be careful of the softness factor with many lens at these f values
so for safety - just push ur f value out (i.e. down e.g. to f 5.6, and more so for for group shots)


Canon EF 50mm F1.8 II Lens Review: 3. Test results (APS-C): Digital Photography Review
Canon EF 50mm F1.8 II Lens Review: 5. Conclusion & samples: Digital Photography Review

"Studio Tests - APS-C format

.. The Canon 50mm F1.8 generally gives a pretty good account of itself on APS-C, marred only by soft corners at wide apertures. Aside from that the lens does very well, matching the EF 50mm F1.4 USM at common apertures and possibly even a bit sharper in the centre (& I would agree with this based on my own lens - F1.4 can be even softer at times). It's much sharper than any of the EF-S zooms we've tested, for example it's simply streets ahead of the 18-55mm F3.5-5.6 IS kit lens.

Resolution

The Canon 50/1.8 is quite sharp in the centre wide open, but the corners are noticeably soft, and the lens needs to be stopped down to F3.5 when sharpness in these regions is important. Best results are obtained at F5, and beyond this diffraction slowly takes its toll; as usual on APS-C, anything smaller than F16 should be treated as emergency only.

Chromatic Aberration

Lateral chromatic aberration is essentially a non-issue (a fundamental characteristic of the symmetric Gaussian design of the lens). There's also little sign of the blue 'colour blur' which plagues the EF 50mm F1.4 USM at wide apertures. This is about as well-behaved as you'll ever see.

Falloff

We consider falloff to become perceptible when the corner illumination falls to more than 1 stop less than the centre. As usual for a full-frame lens used on APS-C, there's simply nothing to worry about here.

Distortion

Distortion is very low at just 0.4% barrel, which will be essentially invisible in real-world use."

"Soft corners at wide apertures

Not unusually for a full-frame optic used on the resolution-hungry APS-C format, this lens isn't at its best at wide apertures, and although central sharpness is OK the corners look distinctly soft. In this regard it's worth noting that depth of field is very shallow at F1.8, and real-world results are mainly dependant upon focus accuracy, with the slightest relative movement between photographer and subject resulting in a misfocused image. Of course depth of field issues also mean that the corners of the frame are often out of focus at F1.8 anyway.

Nevertheless, to illustrate this issue here's the latest in our series of educational brick wall pictures. (photo samples provided on dp review) At F1.8 the centre looks a little soft and lacking in detail, but the corners are very soft indeed. Stopping down to F4 improves things dramatically - the centre now looks extremely sharp with well-resolved fine detail, and the corners have also improved significantly (stopping down a little further to F5.6 extracts the best possible performance)." ...

Conclusion - Pros

Excellent image quality when stopped down
Essentially no lateral chromatic aberration
Extremely cheap

Conclusion - Cons

Extremely cheaply built
Harsh and distracting bokeh due to pentagonal aperture
Vignetting at wide apertures on full frame (which only disappears at F3.5)
Inconsistent autofocus in low light (most problematic when using large apertures)


Overall conclusion

The Canon EF 50mm F1.8 II may be one of the cheapest lenses currently on the market, but its optics belie its lowly price. As befits a classic standard prime lens, it's very sharp when stopped down (especially in the centre), shows minimal chromatic aberration, and has relatively low distortion; APS-C users will also benefit from extremely low vignetting. In most regards it comes very close indeed to its much more expensive bigger brother, the EF 50mm F1.4 USM, lagging marginally behind in corner sharpness at any specific aperture. The only real blight in imaging terms is the lens's bokeh, or rendition of out-of-focus backgrounds, which is anything but smooth with a distinct tendency to render bright highlights as obvious pentagons (it's a pity Canon didn't choose to use a diaphragm with 7 or 8 blades instead of 5). ...

Given the price, it seems reasonable to assume that this lens will overwhelmingly be used on APS-C bodies, and in this context it's worth pointing out that it's sharper than any of the EF-S lenses we've tested so far (the 18-55mm F3.5-5.6 IS, 18-200mm F3.5-5.6 IS or even the 17-85mm F4-5.6 IS USM, which is at its best at 50mm). We suspect full-frame users will on the whole be buying more expensive optics, but to overlook this budget option completely would be a mistake, as it can demonstrably perform very well even on the 21Mp EOS-1Ds Mark III (and therefore also 5D Mark II) at its optimum apertures. That F1.8 maximum aperture lets in more than four times as much light as a typical kit zoom, and so allows shooting in low light while keeping shutter speeds relatively high; this therefore provides a useful alternative to IS when the aim is to keep moving subjects sharp. It also enables the user to experiment with selective focus techniques impossible with slow zooms. ..."


regards
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Last edited by kpy; 09-10-2009 at 01:51 AM.
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  #17 (permalink)  
Old 09-10-2009, 01:54 AM
kpy kpy is offline
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some folk also like to use bigger zooms or bigger fixed lens for portrait work

e.g. a descent 100m plus zoom/fixed lens

it can be another way to help to soften/blur out the background

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