Image clarity, aperture and EOS 1.6x

[x_wang]

<p>This is the back of Saint Modwen church in Burton-upon-trent, England. It's not a very careful shot, I liked the scene very much, but I had to be quick, because one of the geese was going to stand up...I didn't have time to change settings too much(Bracketing).<br /> The quality of the image is poor, strong CA, took me a lot of time to get rid of it..The main problem of this photo is the church is not sharp, even it has been sharpened on PS. The photo was taken in a bright day light,(1:40pm) I tried to get a good sky,but the church was underexposed and had to be brightened up on PS. I just wonder why it is not sharp, if it is too much underexposed (S:750;F8) so that the detail can't be brought back. It just occured to me if the old film camera's rough guide lines I was told when I first picked up still work on 1.6x digital camera. Eg. large aperture and slow shutter speed in the morning and late afternoon, reducing the apetrue and increasing shutter speed towards the bright time of the day..but this is 1.6x crop, not full frame.Does it still work in the same way? I felt it didn't work on my bridge camera before. For 1.6x,it would be closer, does it affect the aperture settings? I don't know if I made myself clear.. This photo's setting was wrong, anyway. It should be around about F11-16,in my film camera's mind. Should it be 16-22 at standard lens on digital 1.6x? or more precise settings? If so,I would think that it could be the aperture is too large caused the unsharpness. But I had another look of a photo which was taken about 45 minutes later in a different location, a closer shot with aperture F10; S1000., the church building doesn't seem very sharp either even the building was more facing the sun. So, I wonder if it is aperture or underexpose. Or camera shake again,S750/sec and S1000/sec should be OK, shouldn't it? All comments, criticisms.. any ideas, thooughts..for a good discussion are welcome. Thank you.<br /> Jasmine<br /> <br />About the church: According to wikipedia The current church building, which dominates Burton's market square, was begun in 1719, first used for services in 1723, and finally completed by 1728. [The church itself] is built in red sandstone and comprises an aisled five-bay nave with galleries on the north, west, and south, an apse, and a western narthex with central tower, north and south gallery stairs, and internal porch. Designed in a Classical style by the brothers Richard and William Smith of Tettenhall.. For more detailed information, please go to: http://en.wikipedia.org/wiki/St_Modwen's,_Burton_upon_Trent</p><div></div>

[jaydesi]

<p>Everything except the trees ad the sky have an almost paint like quality, which I'd say is more likely to be something you did in post processing. Where was your focus point? At the distance you are from the church, f/8 should have been sufficient if you focused on the proper place. It's not camera shake, because everything in the image isn't equally unsharp. I'm not an expert by any means, but I'd have a look at your post processing technique...how sharp/blurry do the geese and church appear straight out of the camera, before you did any manipulating?</p>

<p>Check out a DOF calculator online, or an app for a smartphone if you have one. There are many available for free, and that could help pinpoint if DOF is your problem at the aperture you selected.</p>

 

[matthew_moran]

The picture looks great on my phone.

I'll have to take your word that the

church is not sharp. What focal length

did you use? I ask because at F8 and a

fast shutter speed, the only thing I can

think of that would make the church

soft is that it is not in the depth of field

for the image. If you focused on the

streetlight or duck, and the lens was

normal or telephoto, then I can easily

imagine the church being soft.

For example, assuming you focused on the duck at 20 feet away and the church is 50 feet behind that, then any lens longer than about 35mm will not have sufficient depth of field at f/8 for the church to be in focus. Of course I'm making some wild assumptions about the distances.

[x_wang]

<p>Thank you Jay. I brightened up the church and foreground a lot, and darkened the sky by using layer mask. You see, it was in the middle of the day, the light contrast was very strong..I'll upload the original photo.<br>

Jasmine</p><div></div>

[x_wang]

<p>Settings:Canon 50D;EF-S18-200mm f/3.5-5.6 IS;S750/sec;F8;ISO200; Focal lenth 28mm;Manual; Handheld;Time:1:40pm.</p>

[x_wang]

<p>Sorry Matthew, I didn't see your comment.<br>

I see your point. It was a snap shot,I wanted to put the geese in the photo but I don't think that I focused on the geese. The contrast of the light was strong (1:40pm), not an ideal time for taking photos, but I only take photos when I go out, mostly in a foreign location.SO I have no choice. If I had time, I perhaps would do bracketing. But if I didn't , like this one, I can only mangage to be sure not blown out the high light and see what I can do on PS later. Because as I said that I had looked another photo at different location 45 minutes later,smaller aperture, higher speed,more facing sun, it was not very sharp either, so I wonder if it is too much underexposed. That means I can't save both on single photo, if the contrast is too strong...<br>

I'll put setting on..<br>

Thanks again. </p>

[LenMarriott]

<p>Jasmine, Thanks for including the original file. It helps point toward the trouble and explains why so much post processing is required. It shouldn't be that far out. First, it appears underexposed which you already suspected. Not sure how that happened as 1\750@ f8 seems about right for a sunny scene with ISO 200. Seems to be some vignetting @28mm but I'm not sure that means anything. Some controlled testing of your camera\lens seems to be in order. Let us know how you make out. I offer my attempt to put things straight. Best, LM.</p><div></div>

[jaydesi]

<p>Thanks for the original picture. It does look like you may have gone heavy with the saturation. Maybe lower that a bit, and increase the contrast to bring out the edges a bit? You could selectively saturate the sky more heavily if you want it to be that deep blue. Just some ideas. I have a lot to learn in post processing, so I'm sure others will chime in with more specific, and probably better, advice.</p>

[mikemorrell]

<p>If you keep getting problems, then I think Len's suggestion to get your camera + lens checked is a good one. I've never seen vignetting like this - could this be just a lens cap getting in the way?<br>

The other photos in your portfolio look fine (and don't have the strong vignetting). Is it possible that the autofocus just didn't work correctly in this photo? Perhaps because you were exposing for (and autofocusing on) for the sky. Or because of your autofocus settings? <br>

Hope this helps,<br>

Mike</p>

[x_wang]

<p> Hi Len,<br>

How are you,? Nice to hear from you.<br>

Thank you for the MOD. We drifted a bit... My concern is why the church is not sharp. Your MOD is good,len. I brightened it up a lot more than you did, the reason only was that I was trying to get the picture closer to what I saw. It was really bright. Believe it or not, it was the last bright day (16th, April) in England. Since this day,it's been raining every day.Even today!<br>

The church part had to be underexposed, because I had to preserve high light. The question is how much, perhaps. If it is too underexposed, I can't get detail back.Normally speaking, single exposure is not enough at such high range. I wonder if it is the case or some other reason made the church not clear. The setting was not quite right, in my film camera's mind,it would be better at F11-16 ( I'm sure that you are more experienced than I am with film camera :-)). But this is digital 1.6x, not full frame, and focal lenth matters as well, I guess. It's just too technical for me to work out.<br>

The black part on the original photo was the len hood, not vignetting .. :-)<br>

Thanks a lot, Len.<br>

Best wishes.<br>

Jasmien</p>

[Tim_Lookingbill]

<p>Can't tell sharpness from DOF or camera settings in this small jpeg. Editing it to look correct did take some wrangling in Adobe Camera Raw but find the image looks naturally sharp once clarity and contrast is established according to the ratios offered by a bright sunlit day with the sun positioned approx 45 degrees off horizon.</p>

<p>I'ld have to see the full size jpeg to tell if there's softness from DOF diffraction, camera sharpness settings or where point of focus is actually established.</p>

<p>But here's my edit to correct for how the scene should look bathed in sunlight.</p>

<div></div>

[x_wang]

<p>Sorry, Mike. i didn't see your message came in when I wrote to Len.<br>

Yes, it is the lens hood. I didn't bother about it too much when I took the photo. I thught when I straighten the photo, the top would be gone...or crop off. I left the editting margin...Thanks again:-)<br>

jasmine</p>

[x_wang]

<p>Thank you Tim. I'll see if I can upload original larege Jpeg file. i thought only 700pixels .. Thank you again.</p><div></div>

[x_wang]

<p>Sorry, I forgot. I just had a look from Canon' s software. I don't how to find on PS. The AF point is on the centre of the image. ( on the church wall).<br>

BTW, how did you measure the light "with the sun positioned approx 45 degrees off horizon.".. I would like to know, sounds very smart and interesting:-)<br>

Thanks again.<br>

Jasmien</p>

[scott_ferris]

<p>x wang,</p>

<p>The first problem you are encountering by using your film advice on digital is that the two mediums work quite differently. Digital has a linear response whereas film has shoulders, this gives film much more latitude for scenes with challenging dynamic range.Incidentally, there is no difference in <em>exposure</em> advice for different formats, the EV is the same from a phone camera to a large format plate camera (thought the same aperture from the same place and scene gives you ever greater dof as your format gets smaller). It is not technical and needs no user thought, just go with your cameras meter and make adjustments relative to the scene before you. This scene would have metered close to correct due to large bright and dark areas so to hold detail in the dark areas I'd use a little positive exposure compensation.</p>

<p>With digital it is important when you are trying to keep shadow detail to <a href="http://en.wikipedia.org/wiki/Exposing_to_the_right">"expose to the right"</a>, this is because it is much more efficient to darken a digital image than it is to lighten it, of course you do need to be aware of clipping, but is is surprising how badly you can clip and recover, don't forget a blinky in playback just means at least one channel is clipped, it does not mean all detail is lost, all detail is not lost until all three colour channels are clipped.</p>

<p>The answer to your above image is to over expose until the clouds clip, then lower exposure in post.</p>

<p>Working in RAW gives you considerably more control too, as the dynamic range and bit depth are larger. Were I shooting this scene I would have shot RAW and used +0.5 to +1.0 exposure compensation.</p>

<p>Now why is the church blurry? Well it has lost clarity for two reasons, it is underexposed, which we have covered, and it is at the limits of your dof. Your EXIF says you were focused at 5 meters, that puts maximum dof at 133 meters, but that is a maximum, not the optimum, the optimum is just 5 meters away, at 134 meters your subject is considered out of focus, I would suggest that the church tower is probably 100 meters away and is blurred because that is what something so close to the limit of dof when the focus distance is 5 meters looks like. The trees to the right are closer than the church so are nice and sharp.</p>

<p>To have optimised sharpness throughout the image the technique you needed to use was <a href="http://www.cambridgeincolour.com/tutorials/hyperfocal-distance.htm">hyperfocal focusing</a>, that is focused behind the birds to get both the birds and the church sharper.</p>

[scott_ferris]

<p>P.S. The shadow of the lamp post is how to easily determine where the sun was, if the shadow is the same length as the post is high then the sun is at 45 degrees. This assumes the shadow is at a 90 degree angle to your line of sight, ie across the frame.</p>

[William Michael]

<blockquote>

<p>I just wonder why it is not sharp, if <strong><em>it is too much underexposed (S:750;F8) so that the detail can't be brought back.</em></strong></p>

</blockquote>

<p>Yes this appears to me to be the whole problem, in one simple statement.<br>

The SHADOW DETAIL is too difficult to recover from the UNDEREXPOSURE – this then APPEARS as “lack of sharpness”.</p>

<p>Yes - F/8 @ 1/750s @ ISO200 is an expected exposure for “front lit sun”.</p>

<p>HOWEVER:<br>

You are quite high up (on the earth, latitude)<br>

That is NOT front lit sun on the Main Subject – the <strong>Main Subject is mainly in Deep Open Shade </strong></p>

 

<blockquote>

<p>It just occured to me if the old film camera's rough guide lines I was told when I first picked up still work on 1.6x digital camera. Eg. large aperture and slow shutter speed in the morning and late afternoon, reducing the apetrue and increasing shutter speed towards the bright time of the day..but this is 1.6x crop, not full frame.Does it still work in the same way? </p>

</blockquote>

<p>I am not really sure what you are getting at here, but in respect to Film vs. Digital for this type of lighting scenario – Film will win every time for a one shot capture as film has a much wider dynamic range.</p>

<p>If you wanted to capture critical detail in the walls of the Church, you needed to expose correctly for that detail, which (using a digital camera) would mean you will lose the detail in the clouds, they would be blown.<br>

There are two main options – </p>

<p>For One Shot - compromise get the clouds to blow a little bit in part of their highlights and gain more detail in the deep shadows of the Church – you could quickly shoot a bracket for that: you might consider that walking the countryside with your camera you have it set to shoot a bracket of three exposures, as your default.</p>

<p>For multiple shots – use High Dynamic Range Technique.</p>

<p><a href="../photo/10175853&size=lg">This is a sample exposing only one shot, where the Subject is in shadow and the exposure is a compromise between being correct exposure for it.</a><br>

The lighthouse is actually under-exposed but not too much as reasonable detail - apparent sharpness – could still be brought out.<br>

But some of the sky must be blown out because of the limitation of the Dynamic Range of the Digital Medium:</p>

<p><img src="http://d6d2h4gfvy8t8.cloudfront.net/10175853-md.jpg%20" alt="" width="680" height="340" /><br>

<strong>"Lighthouse at Sunrise"</strong><br>

<strong></strong> <br>

<strong></strong><br>

WW </p>

[William Michael]

<p>Addendum:</p>

<p>I was writing at the same time as Scott.<br>

I didn’t even look at the EXIF as I was too concerned about explaining the Underexposure. (mistake not considing all the possibilities)</p>

<p>Scott wrote:<br>

<em>“Now why is the church blurry? Well <strong>it has lost clarity for two reasons</strong>, it is underexposed, which we have covered, and <strong>it is at the limits of your dof</strong>. Your <strong>EXIF says you were focused at 5 meters, </strong>that puts maximum dof at 133 meters, but that is a maximum, not the optimum, the optimum is just 5 meters away, at 134 meters your subject is considered out of focus<strong>, I would suggest that the church tower is probably 100 meters away and is blurred because that is what something so close to the limit of dof when the focus distance is 5 meters looks like.</strong> The trees to the right are closer than the church so are nice and sharp.”</em> </p>

<p>I concur and amend my comments accordingly:<br>

There are TWO reasons for the softness of the Church.</p>

<p>WW</p>

[William Michael]

<p>One (quick) method of addressing the lost shadow detail is to increase repeatedly the % shadow using Shadow Highlight.<br>

Here is a comparison of the original large JPEG and a repeated 4 times, 2% increase in the shadows at 100% Tonal Width – no other manipulation.<br>

The original is on top:<br>

<img src="http://d6d2h4gfvy8t8.cloudfront.net/15612213-lg.jpg" alt="" width="490" height="700" /></p>

<p>There is also a product “Focus Magic” which can address moderate OoF and also moderate camera or subject movement.<br>

Here a comparison of the shadows increase and Focus Magic set to address the OoF only.<br>

Again the original is on top:<br>

<img src="http://d6d2h4gfvy8t8.cloudfront.net/15612212-lg.jpg" alt="" width="490" height="700" /></p>

<p>As an interesting side point - when using the Focus Magic Program, I also detected very slight movement, (i.e. I noticed that FM would make the image even sharper if camera movement correction adjustments were selected).<br>

Most noticeably the “movement” was present on the front façade of the Church – obviously the Church was not moving so therefore it is likely that the camera was?<br>

Perhaps this finding gives credence to the adage of the best shutter speed is a tripod; and perhaps 1/750s was not fast enough – I am not betting any Mars Bars just passing on the facts as they happened – these findings might just be an anomaly in the FM program, I am not sure <br>

<br>

Here is the final image with only the 4 small increases in shadow detail and the FM applied to OoF (and it has been straightened):<br>

<img src="http://d6d2h4gfvy8t8.cloudfront.net/15612214-lg.jpg" alt="" width="500" height="700" /> </p>

<p>WW</p>

[Tim_Lookingbill]

<blockquote>

<p>BTW, how did you measure the light "with the sun positioned approx 45 degrees off horizon.".. I would like to know, sounds very smart and interesting:-)</p>

</blockquote>

<p>Went by the lamp pole and its shadow in the foreground next to the geese. Makes a 45 degree angle or close to it lining up tip of shadow to top of lamp.</p>

<p>What I can't figure out in your image is why the farthest to the left brick wall isn't lit by sunlight but the cylindrical outcrop next to it is. Must be slightly off angle to the sun or lined up with it. The front side of the brick steeple facing the viewer isn't brightly lit either like the grass. </p>

<p>Is there some kind of large building out of frame on the left blocking the sun on these surfaces?</p>

[James G. Dainis]

Judging by the shadows, I would say that the facing facade of the building is slightly more than perpendicular, more than 90 degrees, to the sun. Ergo, it would be in shadow.

[x_wang]

<p>WOw.. Thank you so much SCott, William, Tim and James. I have to let you know a bit of my DOF.:-D<br>

I don't know much about technical matters and photography, I only take photos when I travel., but I do enjoy learning from you guys..<br>

----------------------------------------------<br>

Thank you Scotts. The reason that I thought of the film camera matter is the DOF. I was trying to work it out if it was the F number made the picture blur. since it had been mentioned a few times..I'm a bit confused about the DOF. 1)How do I understand "EXIF says you were focused at 5 meters, that puts maximum dof at 133 meters"? The AF point is on the church wall. see the red dot. Could you explain further? 2) When I took the photo, I didn't have time to do bracketing. I used manual at "-" stop, I can't remember it was "-1 or -2" now, in order to preserve the high light not to be blown out. It was the middle of the day, the light contrast was strong. I thought that I could bring the church's details back.<br>

. -------------------------------------------<br>

Thank you William. As I said that the reason that I thought of the film camera was DOF was mentioned. I thought that if F8 of 1.6x is not sufficient enough to get a clear picture of the church, the DOF would be smaller on 1.6x, but, it should Not affect the clarity of the focal point part. No matter how small the DOF is , I should have a clear part on the image. And then, I thought if I want to have the same DOF as film camera, on 1.6x camera, I should change F number further. Eg, if I use F8 on film camera, I should use F11 or 16 to get the same DOF as film camera. That's why I said the setting was wrong. So, I actually got the conclusion. Thank you very much. The unsharpness was caused by too much underexposure and possible camera shake, or I blame to the stabilizer is not effective as the manufacturer said:-D. I can't do any thing about the camera shake, because I don't use tripod, simply I can't carry it. Now, back to the underexposure. My simple question is: At what degree, the detail can't be brought back on PS? Let's say, how many stops on the camera? Does colour should be in consideration as well? When the contrast of the light is very strong, single photo can't cover all the range, multi-exposure is necessary. By what mean that I can tell that single won't work. I explain a little further.. I intend to travel light, and I don't stay in one place very long. Whatever the light condition, I have to accept it. Normally, when the light contrast is too strong, I do bracketing, but I ended with too many 3x photos, HDR does not always work. So, I thought that if I can take one photo, I would stick on single photo, but it's not safe, once I lost the photo, I can't go back. Could you tell me what kind of histogram that I should watch out? I mean, what is the warning sign? The sign tells me single photo wouldn't work, I have to do bracketing to cover the whole range.I mean, I understand that if they are on both ends and cut off the top, they perhaps wouldn't work. I'd like to have a precise picture in my mind. Thank you.<br>

. --------------------------------------------------<br>

Thank you Tim, How observant:-), Very cool..:-D, I thought that you have a secret weapon..thanks again. -----------------------<br>

Thank you again, James.<br>

------------------------------------------------------------------<br>

Thank you all very much. I really enjoy learning from you all.<br>

Jasmine</p><div></div>

[James G. Dainis]

To reiterate - According to the EXIF data on your photo you were using:<P>

 

<P>Canon DOS 50D<BR>

Focal length - 28mm<BR>

Focus distance - 4.96m (16.5 feet)<BR>

Aperture - f/8.0<BR>

Shutter speed - 1/750<BR>

ISO - 200<p>

 

Your point of prime focus was not on the building but perhaps on the geese or lamp post. As Scott pointed out:<P>

 

"Your EXIF says you were focused at 5 meters, that puts maximum dof at 133 meters, but that is a maximum, not the optimum, the optimum is just 5 meters away, at 134 meters your subject is considered out of focus, I would suggest that the church tower is probably 100 meters away and is blurred because that is what something so close to the limit of dof when the focus distance is 5 meters looks like. The trees to the right are closer than the church so are nice and sharp."

[scott_ferris]

<p>Jasmine,</p>

<p>You are correct in that the aperture affects the dof, a great site full of explanations <a href="http://www.cambridgeincolour.com/tutorials/depth-of-field.htm">is here</a>. Give the site a few moments it is a great learning tool.</p>

<p>As an aside, to get the dof and angle of view from the same place a 50D requires less aperture than a 35mm film camera. So f8 on your 50D is equivalent, assuming the shot is the same, as f11 on your film camera. If you use the same focal length on the different cameras the dof is slightly shallower on the 50D, but of course the framing is very different.</p>

<p>I got the focus distance from the EXIF of your shot, this is written to the image file at the time of capture.</p>

<p>Here is the EXIF from your shot.</p><div></div>

[scott_ferris]

<p>For an example of what can be recovered in post IF you use RAW, I have posted these two screenshots before. The first is a misfire at the ground in LightRoom with the channel blown warning in red.</p><div></div>