yannig

<p>Strangely, my camera doesn't always behave like this. In better lit conditions it seems to be ok. In the dark it is always off by the same amount ...</p>

<p>With the 50/1.8 II lens, same result ...</p>

<p>Upper AF point with flash.</p><div></div>

<p>Lower AF point in attachment.</p><div></div>

<p>Hi,<br>

Last saturday I was on assignment, photographing a folk band with my 50D. During and after the shoot I noticed most of the pictures in some series were out of focus. I focus on the eye with the upper AF point, and the complete face is unsharp. It isn't motion blur, it's a front focus issue. I know this because the shoulder was sharp every time.<br>

I just investigated this issue a little further, and the problem seems to be down to ONE AF point, the upper one. All AF points work fine, they give me correct focus every time, except for the upper one.<br>

The test I did was like this: I put a ruler on a table, parallel to the sensor plane. Gear: Canon EOS50D, EF 85/1.8, ISO 2000, F/1.8, 1/250s (manual exposure mode). There are no AF micro adjustments whatsoever. All pictures were taken by focusing with one AF point, and NOT recomposing.<br>

I focus with the upper AF point in Manual exposure mode on the 30cm mark, and take a picture. I focus on a point in the background, then I focus once again on the 30cm mark, and take another picture. I then repeat this process and take a third picture. All three pictures are equally unsharp (upper.jpg).<br>

To check how bad the focus is, I put the rule in a 45° angle compared to the sensor plane, and repeat the process. The pictures in attachment are taken with the ruler at 45°. With the upper AF point, the focus is around the 43cm mark. With the lower AF point, the focus is at 30cm, where it should be.<br>

Additional tests:</p>

<ul>

<li>Same test, but with the bottom AF point (lower.jpg). This picture is sharp at 30cm.</li>

<li>Same test, but with the center AF point: sharp at 30cm mark.</li>

<li>Same test, but at ISO100 with a 580EX II firing at manual mode and with the upper AF point (upperflash.jpg): unsharp.</li>

<li>Same test, but with my EOS 5D Mark II: sharp with all AF points.</li>

</ul>

<p>I thought this was down to a dirty AF sensor, so I cleaned my main mirror, and the smaller mirror below the main mirror (hard to do!). I blew some air in the sensor box to try and remove some dirt that may be in there, but after all, the results were exactly the same.<br />I also cleaned the lens once more (even though it was already clean).<br>

So, any thoughts on what might be causing this, and what I could do to resolve this? Using another AF point isn't a workaround I'd like to live with.<br>

Kind regards,<br>

Yannig</p><div></div>

<p>I use mine with the GenericPnP driver, and this works fine.<br>

I had the problem with softness as well, but that seemed to be the VGA cable i was using. I replaced it with a thicker cable, and the image improved a lot!</p>

<p>This driver seems to be 32bit only. On my Windows 7 64bit it isn't recognized as a valid driver. It work, but i'd feel better when i was using a dedicated driver ;)</p>

<p>Bump ...</p>

<p>Hi,<br>

I'm noticing something strange in an icc profile i made recently. When i look at it in a gamut checker (Monaco GamutWorks), it shows some strange defects, in two places data seems to be missing.</p>

<ul>

<li>Around L=37 there's a gap at the green/blue side.</li>

<li>Around L=11 there's no gamut anymore at all, but at L=10 there's one again a blotch!</li>

</ul>

<p>You can download the original icc file here:<br>

ftp://www.pantoon.be/MIvinyl.icc<br>

In the attachment you can have a look at the icc file opened in GamutWorks.<br>

My question: what's causing this gap?</p><div></div>

To be honest, i don't see it ...

^^ I forgot to say, a 28/1.8 that's optically better ...

28/1.8 (IS) USM for low-light work, and a stabilized macro lens would be interesting as well.

Steve, the image at ISO1600 shows a lot more noise than the one at ISO100! Still, it doesn't look that bad. I'd only like to see some decent available light portrait shots at high ISO.

Thanks for the quick responses.

<br><br>

I already decided to take it with me to Italy and not use the IS, image quality seems fine in the shots i already

took. Still, i think it's my favorite lens (don't get me started ;)) and i hate to see something like that happen.

<br><br>

Yes, i must concur that having IS is yet another thing that can go wrong. My 70-300 has already been sent in for

an alignment problem. Caused by the IS or not, i don't know, but the only two lenses i'll have sent in are my

lenses with IS.

<br><br>

On my trip to Italy i'll do fine indeed without IS (most of the time ...). But when i'm back i'll have to get

back to taking pictures at dark places. I often find myself shooting at ISO1600 F/2.8 at 1/20s or slower ... (<a

href="http://www.flickr.com/photos/nogood/sets/72157606499335632/">here for example</a>)

- 85/1.8: Best one. Love this lens on my 400D. The only downside is the fringing ...

 

- 50/1.4: On my wish list. I take a lot of available light pics, and i want to go faster than my 50/1.8 can go!

It's pretty good for portraits as well.

 

- 100/2.8 (macro?): Already too much compression on my 400D, plus it's _slow_ in low light. It's happened that my

subject was gone when my 100/2.8 was still hunting.

Last weekend i was shooting at an indoor event when i changed to my 17-55. I wanted to shoot something (that's

what i do with my camera!), looked through the viewfinder, and saw a VERY shaky image! Apparently my IS made it

vibrate heavily on the vertical axis.

 

I removed the lens, cleaned the contacts (lens + body), removed the battery, my grip, CF. I tried it again, but

still the same. At 55mm it still works perfectly fine, but when i zoom out to around 45mm the shake kicks in,

with its peak at 35mm. The shake stays until the IS stops. It vibrates with a very high frequency.

 

My other IS lens (70-300 4-5.6 IS USM) still works flawlessly. My body is the EOS 400D.

 

I know i should send it in (still in warranty), but i'm leaving for Italy this weekend, and after that i've got

some jobs. I really can't miss this lens right now.

 

So, has anyone witnessed anyhting like this before? Or better, does anyone have an idea what i could do to solve

this?

I wouldn't ...

17-55: This is my allround lens. In the beginning i was fighting buyers remorse, but that soon vanished. The 17-55 is my fastest, and sharpest lens. I think the 17-55 will give you better speed (focus wise and light gathering wise), and better sharpness! Get the hood!

 

For lowlight photography, i use the 85/1.8 and the 50/1.8. The extra stop and a third are worth it ...

 

Get all of them ;)

- The AF assist beam from the flash can easily be disabled via the custom functions. The downside is that

focusing can become hard (AF doesn't easily lock).

 

- Pointing the flash in the right direction when using the off-shoe cord, can be a little trick, but you'll get

the hang of it. And i've noticed that you don't really have to point that accurately ...

 

- FEC is indeed very important when using flash in the dark. My "set" button is set to FEC (this is faster than

changing it on the flash itself). Most of the time my FEC is set to around +1, so that's a lot more power than

you'd expect, but at least it's consistent!

I'm not at all impressed with diffusors. They waste batteries, create color cast, and don't have much effect anyway. They make the light source only slightly bigger, this can't be compared with bouncing off wall/ceiling.

 

What i've been using for a while now, is the Canon off-shoe cord. I hold the camera in my right hand, and the flash (attached with the cord) in my left hand, as far as possible to the left and top. This doesn't waste battery power, and creates a much more natural light. The only difficulty is pointing the flash right at your subject.

 

Focus mode: this depends on the subject of course. At the parties i go at, people dance, and so i use AI servo. When people pose, use one shot AF.

 

Something often underestimated: adjust your lcd brightness to the environment! With your LDC set too bright for example you'll have a hard time checking exposure (check your histogram!).

 

Nadine made some very good points; always look for something colorful in the background, and use your flash exposure compensation to get the right subject exposure.

Godfrey,

 

I'm not looking for an answer why my prints are different from Photoshop and Lightroom. My prints from Photoshop are exactly what i want them to be. When i got this printer (HP Photosmart B9180), i tested all the possibilities; printing from different apps, using software CMS, hardware CMS, etc. The difference might be caused by the fact that i print straight from RAW in Lightroom, and that i print from an AdobeRGB JPG in Photoshop. Anyway, i'm not looking for a solution or anything.

 

I justed wanted to help Michael, but if i had read your posts prior to posting, i wouldn't have posted in the first place.

 

FYI: My color managed workflow is like this: the room i'm in is painted white (3x5mﾲ) illuminated by a 58W/965 TL lamp. I have a dual monitor setup, the main screen is an old LaCie CRT, the other one is a cheap LG CRT. The screens are calibrated using an Eye-One Pro (not the i1display) in Monaco Profiler 4.8.3. I used to make my output profiles myself, but since the B9180 that's no longer necessary. The profiles made by HP respond very well to the results i'm used to during my day job. I check the results with Altona Visual (...).

 

Anyway, i've got the feeling i can still learn a thing or two from you guys ;)

Oh man, i was late with my answer :) I opened this thread a few hours ago, and didn't see the responses until answering.

 

You might ignore some things i said, i was just trying to give a "birds and bees" explanation ;)

Well, color

management isn't a

simple matter,

that's why these

things aren't

simple. And that's

why giving a simple

answer isn't always

possible.

 

A colour profile

(.icc, or .icm)

defines the

collection of colors

a device can show,

print, measure, ...

Every single device

can handle a certain

collection of colors

("gamut"). There can

be very big

differences between

devices.

 

sRGB is often the

default profile for

several reasons.

Here are a two; it's

pretty limited, and

it often more or

less matches the

gamut of your

screen. Adobe RGB is

a lot bigger, but

most screens can

only show a small

part of this gamut.

 

So what's the reason

not to use sRGB?

Well, your printer

probably can print a

lot of colors that

sRGB doesn't

contain. So, when

you take pictures in

sRGB you're probably

discarding colors

that could be saved

when you were using

AdobeRGB. AdobeRGB

for example contains

more saturated

greens, blues, and

lighter shades of

magenta and red.

 

Look at this image:

 

http://farm4.static.flickr.com/3115/2590745920_a955b6653f_o.jpg

 

The yellow blob/line

is sRGB, the blue

line is AdobeRGB.

 

You should use

AdobeRGB if you know

what you're doing,

if you can configure

every link in the

process to use

AdobeRGB. When you

are using cheap

photo paper, it's of

no use to use

AdobeRGB, since the

paper will prevent

having a large

gamut.

 

Here's a pic that

shows the difference

between the gamut of

my high-end CRT

screen, and the

gamut of my HP B9180

on HP Advanced

Glossy PP:

 

http://farm4.static.flickr.com/3151/2589911307_05c10bb6df_o.jpg

 

The white blob/line

is the printer, the

red is my screen.

 

Btw, when judging

colors on your

screen, you'll need

to have proper

lighting, and have

your screen

calibrated (or use

the right profile).

When this is not the

case, good luck ;)

 

Why is this so

difficult? The

amount of different

colors that we

encounter in life is

endless. When we

take a picture our

camera renders these

colors to a small

selection (sRGB or

AdobeRGB). We then

would like to see

them on our screen,

which can show only

a small collection

of colors as well.

So a conversion will

have to be made to

choose how the out

of gamut colors will

be rendered on our

screen. Then we'd

like to print the

photo with a certain

printer, with some

kind of ink, and on

some kind of paper.

Each part has an

effect on the color

gamut we can

achieve. Color

management is a

complicated system

that tries it's best

to make sure that we

loose as little

colors as possible,

and at the same

time, tries to show

these colors as

lifelike as

possible. Of course

this is only

possible when all

devices are properly

configured, and when

the environment is

appropriate.

 

If our world, our

screens, our

cameras, our

printers, our

scanners, etc would

work in sRGB,

everything would be

easy. And dull.

 

Godfrey; i'm using a

completely

calibrated workflow

(from my lamps, to

my screens, to my

paper, ...), and i

get different

results from

Lightroom and

Photoshop. There are

still some things i

could check, but

i've wasted enough

photo paper ;)

Are you sure

Lightroom works in

ProPhotoRGB?

I believe you do it using "EOS Utility".

It's important that you print your pictures using the same colour space as the one in your file. If you shoot in sRGB, and don't convert to something else, make sure you print them in sRGB.

 

Where do you print from? Straight out of Lightroom?

 

I'm very aware of colour management, and i find the results i get from Photoshop much better than what i get from Lightroom. Btw, i use an HP Photosmart B9180, and my complete workflow is AdobeRGB.