lalon_karim

<p>Most funny thing about IR and dpreview is, they don't even use same exposure for comparing different cameras. If for the same t stop, same shutter speed and same scene lighting, one camera needs ISO 6400 and another camera needs ISO 12,800 , they just change the exposure so that both camera use the same ISO value. How can that be a fair comparison? At least dxo knows these things and takes care of.<br>

But dxo's single number "rating" is very misleading, you have to look at the graphs to really understand and compare cameras. And you also have to understand that they do not have any weightage on resolution (where medium format cameras specifically shine).</p>

http://davidnaylor.org/blog/2010/04/the-myth-of-the-megapixel-myth/

<p>The higher MP body (D7000) will show more detail with any lens at any aperture. Go to dxomark, and compare same lens on different bodies. The output resoltioun is a combination of sensor resolution and lens resolution. Increasing any of the two increases output resolution.</p>

<p>Download "Studio Portrait" picture style and use it in DPP.</p>

<p>Copied from another forum in which I posted:<br /> "I personally think that, for showing a face on a photograph to represent how the face is recalled/ remembered by us, we have to shoot that person from a distance that is equal to the height of of his/ her eye level (from the ground). This is only a theory, and not a scientific one, so there is no proof available to me. This theory implies that the shorter a person, the closer the distance from which u have to shoot to show the face as-is. It means thet we have to shoot children from a closer distance than adults. [bTW, the goal of photography (art) is not showing things as-is, a photographer (artist) has complete freedom of how he wants to show a person's face. This theory is for u only if u want to show a person's face as-is]."<br /> And here is a demonstration of the effect of subject distance for portrait:<br /> <a href="../leica-rangefinders-forum/00YXLF?start=60">http://www.photo.net/leica-rangefinders-forum/00YXLF?start=60</a></p>

<p>All the photos that I posted were lens distortion corrected in Raw converter. </p>

<p>I had another set of these photos where he was shot from around 8 feet too (along with 4, 5.5, 6 feet). From arounfd 8 feet, he looks fatter than he actually is. I have lost the set.<br />These photos do not prove the theory as there r no shots of other persons who r taller or shorter than him. His height is around 5-7, and his eye levels is around 5 feet 3 inches from the ground.</p>

<p>This one was shot from around 6 feets. People who have seen him personally thinks that this photo represents more like how they remember/ recall him. [see another interesting thing, in both the photos the picture frame behind the person was at same distance from the person. But the further the shot was taken from, the larger the frame ends up in the photo.]</p>

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<p>I personally think that, for showing a face on a photograph to represent how the face is recalled/ remembered by us, we have to shoot that person from a distance that is equal to the height of of his/ her eye level (from the ground). This is only a theory, and not a scientific one, so there is no proof available to me. This theory implies that the shorter a person, the closer the distance from which u have to shoot to show the face as-is. It means thet we have to shoot children from a closer distance than adults. [bTW, the goal of photography (art) is not showing things as-is, a photographer (artist) has complete freedom of how he wants to show a person's face. This theory is only for u if u want to show a person's face as-is].</p>

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<p >I want this one!</p>

<p > </p>

<p >Arie Vandervelden <a href="../member-status-icons"></a>, Apr 03, 2011; 05:53 p.m.</p>

 

<p>"EF-S 50-135/2.8 IS with ring-USM for $600-700."</p>

 

 

<p>Hi Art!<br>

I know that effective focal length of lenses r slightly different than quoted length, specially when focused at shorter distances. But some says that 28-135mm is significantly shorter at the tele end, and thats why I posted that:<br>

<a href="http://www.the-digital-picture.com/Reviews/Canon-EF-28-135mm-f-3.5-5.6-IS-USM-Lens-Review.aspx">http://www.the-digital-picture.com/Reviews/Canon-EF-28-135mm-f-3.5-5.6-IS-USM-Lens-Review.aspx</a><br>

"I should note that, at its 135mm setting, the 28-135 IS has a noticeably wider field of view than my <a href="http://www.the-digital-picture.com/Reviews/Canon-EF-135mm-f-2.0-L-USM-Lens-Review.aspx">Canon EF 135mm f/2.0 L USM Lens</a> or my <a href="http://www.the-digital-picture.com/Reviews/Canon-EF-70-200mm-f-2.8-L-IS-USM-Lens-Review.aspx">Canon EF 70-200mm f/2.8 L IS USM Lens</a> set at the same focal lengths at a relatively short distance. These lenses frame the 1200mm ISO 12233 chart at distances of 4035mm, 4700mm and 4798mm respectively. Focal lengths are rated for an infinity focus distance - so they *should* match at this focus distance if their ratings are correct."</p>

<p>24-105mm is generally sharper than the 28-135mm. But the 28-135mm lens is actually a 28-120mm lens labeled as 28-135mm. U can shoot at it's "135mm" and compare it with any other 135mm lens. U will see that it is actually a 120mm lens at the tele end.</p>

<p>I think more color sensitivity = less color noise and less color sensitivity = more color noise. If a sensor is less color sensitive, it has to apply greater degree of color processing (through color matrix) to match the output of any standard color space (ie sRGB, Adobe RGB etc) which results in more color noise. See at dxomark, Canon sensors are less color sensitive than Nikons' and Canons trully have more chroma noise in my experience. Among the currently available Canon and Nikon DSLRs, Canon 500D has a very low score in color sensitivity and it truly has much chroma noise.</p>

<p>I think people are misinterprating the meaning of color depth/ color sensitivity that is measured in dxomark. From my limited understanding, color sensitivity is nothing but the opposite of chroma noise. More color sensitivity = less chroma noise, less color sensitivity = more chroma noise. It has no relationship with how pleasing the colors will look in output (until the chroma noise is noticable). A P&S camera can have much pleasing color than a full frame DSLR if the manufacturer of the P&S do more research on what colors look more pleasing to most people.</p>

<p>1 more thing I would like to see: 4:3 mode and automatic masking on viewfinder for this. 3:2 aspect ratio does not look good to me for portraits (in both landscape and portrait orientation). 4:3 makes nice composition for portraits easy. </p>

<p>These r the things that I would like to see from Canon (not what Canon is actually going to do):<br>

1. A professional grade 55-200mm f/2.8 lens for APS-C (large constant aperture lens, yet portable, unlike 70-200mm f/2.8)<br>

2. A better quality 18-200mm lens.<br>

3. Weather sealed APS-C body that is lighter than 7D<br>

4. Dedicated in body focus assist lamp.</p>

 

<p>And sharpness of the lens used is another variable too. If a sharp lens is used, u can print larger than from the same camera using a not-so-sharp lens.</p>

<p>... and in contrast: Nikon D90 (12 MPixels) is good for "<em>good 20x30 inch prints, excellent 16x20 inch ones. ISO 3,200 images are surprisingly good at 8x10, even better at 5x7" (</em><a href="http://www.imaging-resource.com/PRODS/D90/D90IMAGING.HTM"><em>http://www.imaging-resource.com/PRODS/D90/D90IMAGING.HTM</em></a><em>). </em>So it seems there is a no single formula for relationship between print size and megapixel.<br>

When viewing distance is concerend I personally like the assumption that minimum viewing distance = diagonal length of the print (or may be 1.25x of diagonal length of the print). U need to stay at least in this distance to see the entire print at a glance.</p>

<p>Don't forget that acceptable print size varies with ISO also. More noise and noise reduction -> small acceptable print size. According to imaging-resource (<a href="http://www.imaging-resource.com/PRODS/AA900/AA900IMAGING.HTM">http://www.imaging-resource.com/PRODS/AA900/AA900IMAGING.HTM</a>), u can print sharp 20x30 print at ISO 100 and 200 from Sony Alpha 900 (25 MPixels). ISO 400 and 800s are good for 13 x 19 inch prints. ISO 1600 and 3200s are good for 5x7 inch prints only!</p>

If we rank Canon DSLRs Signal to Noise ratoiwise, the list will look like this (from highest SNR to lowest SNR camera):

1. 5D Mk II

2. 1Ds Mk III

3. 1D Mk III

4. 50D = 500D

5. 450D = 400D = 1000D (= 40D)

For some of us, the best camera would consist 4 pixels only: 2 for green channel, 1 for blue and 1 for red. The pixels of this camera will be largest ever. In this way, we wil get a camera which will have highest full well capacity and lowest possible noise. But what we can do with the output of this camera is anothor question. Right?

I havent use any of these cameras. But, my opinion is, if u view at pixel level 400D is less noisy than 50D. But if u compare same sized outputs, 50D is less noisy than 400D. See this page: http://www.dxomark.com/index.php/eng/Image-Quality-Database/Compare-cameras/(appareil1)/267|0/(appareil2)/184|0/(onglet)/0/(brand)/Canon/(brand2)/Canon

Go to SNR 18% tab. To compare pixel level noise, select "Screen". To compare noise in same sized outputs, select "Print".

<p>50D and 500D both have rated shutter life of 100,000 (<a href="http://www.the-digital-picture.com/Reviews/Canon-EOS-Rebel-T1i-500D-Digital-SLR-Camera-Review.aspx">http://www.the-digital-picture.com/Reviews/Canon-EOS-Rebel-T1i-500D-Digital-SLR-Camera-Review.aspx</a>). I would go for 500D because of it's light weight. I have 450D and when attached with a 55-250mm lens, I can carry it whole day on my hand. That would not be possible with 40D. But one feature you may miss in 500D is that it does not have microfoucus adjustment. Handy if u have a lens with focus problem. </p>

<p>Wow Ales! I can even see the photogrepher on it's eye!<br>

I think by travel lens, Eugene means a do it all lens that covers (almost) all necessary focal lengths.</p>

<p>http://www.photo.net/canon-eos-digital-camera-forum/00TJ4h</p>