Tag: dynamic range

A little about DxO Mark

Since there has been a lot of interest in this camera after previous posts, I wanted to mention that DxO published their rating of the Nikon D3100 sensor.

DxOMark - Compare sensors

This chart compares the new Nikon D3100 to the highest-scoring APS-C sensor (Nikon D300s) and full-frame sensors (Nikon D3s).

I’ve used DxOMark a lot in passing discussions, and a friend (and recent Nikon D3100 owner) last month mentioned, “I don’t know how to read this.” Whoops!

I had better explain what these values mean.

Continue reading a quick guide to understanding DxOMark after the jump

Posted on by tychay 6

Camera testing bias

Ken Rockwell goes on a tear with his new camera, a medium format digital.

As his habit, Ken Rockwell exhibits a bad case of selection bias. For example, let’s take this quote from the first article:

All the 35mm rangefinders and DSLRs look pretty much the same, and the point-and-shoot is the worst.

I’ve also shown the fallacy of falling for claims of 12-bit, 16-bit or 24-bit image processing in-camera.

As those of us who have done this for a living since the 1980s know, the noise level of any of these sensors is much larger than even 12-bit processing. Throwing more real bits at the ADC only serves to quantize the noise more accurately; there isn’t any meaningful image data needing that precision.

Well anyone can see from his sample the 35mm cameras are not the same: the Nikon D3 exhibits tonality better than the Canon 5D Mk II and the Leica M9, as it should. And those aren’t even the right 35mm cameras to be testing against—I will bet you’ll get nearly the same result as the Mamiya DM33 in the Nikon D3X (with a Zeiss ZF optic on it). He does similar manipulations of outcome bias in order to get the result he is wants to get before hand in his high ISO test.

Continue reading about Ken Rockwell after the jump

Posted on by tychay 6

Canon and Nikon are still the same

Camera Labs compares the Canon 550D (Rebel T2i) to the Nikon D90 at high ISO.

I’ll give you the summary: at high ISO in JPEG comparison, the Canon delivers similar performance but with higher resolution.

This may sound like a surprise, but let’s look at was buried in my article where I mention the Rebel T2i.

Not only that, but the newly minted Canon 550D has nearly the same ISO performance as the Nikon [D5000] and 20% greater resolution—the cost of that resolution is a one stop worse dynamic range

(The Nikon D5000 and D90 have the same sensor design.)

This is the problem with reviews snippets taken in isolation: the Canon 550D and the Nikon D90 are nearly the same (street) price so it may seem that the Nikon D90 is a bad value but this isn’t the case at all. The Nikon D5000 is much cheaper than the Canon 550D and delivers the same ISO performance as the D90, are we to say the 550D is a bad value then? The Canon 550D has the same sensor as the Canon 7D are we to say that the Canon 7D is a rip off?

No. Because the Nikon D90 has a much, much brighter viewfinder and better dynamic range than the Canon 550D—in turn the Canon 550D has a better video mode and higher resolution than the D90. And the Canon 7D tops the D90 with even all-metal construction and a 100% viewfinder (both notoriously expensive to manufacture). Here is a small table:

Cheaper More expensive Pros (upgrade) Cons (upgrade)
Nikon D5000 Nikon D90 higher res LCD, pentaprism,backward compatible AF motor,flash commander mode $250 more, lose articulation
Nikon D5000 Canon 550D 20% higher resolution, higher res LCD, better video $350 more, loose dynamic range, lose articulation
Nikon D90 Canon 550D 20% higher resolution, better video $150 more, lose dynamic range, lose pentaprism
Nikon D90 Nikon D300s 7fps, metal body, 100%viewfinder, two card slots, advanced AF, meters old lenses, pro setup $700 more, lose scene modes
Canon 550D Nikon D300s 7fps, pentaprism, 100% viewfinder, metal body, two card slots, advanced AF, dynamic range,pro setup $550 more, worse video, lose resolution
Canon 550D Canon 7D 8fps, pentaprism, 100% viewfinder, all metal construction $650 more
Nikon D300S Canon 7D 1fps faster, 20% higher resolution, better video $100 more, lose dynamic range, lose 2nd card slot

(My street prices were rounded to the nearest $50.) Plus there is a $100 – $200 rebate if you purchase Nikon bodies with a lens: as I noted earlier, the street price of Canon tends to drop faster and Nikon tries to maintain the price longer but offer rebates instead.

(As for JPEG, that’s a post-processing design decision. Did you know that Nikon’s tend to be undersharpened and have more faithful red channel color? So what.)

The table shows you that basically these cameras have a price interleave that is nearly exactly right. The D90 is the 550D with different tradeoffs; the D300S is the the 7D with tradeoffs. The D90/550D give up similar things to the D300S/7D. I mentioned this before. When it comes to sensors, Nikons tend to have better ISO and dynamic range but at the cost of resolution. I also mentioned this before.

This sort of pixel peeping is going to give you the exact same result that a Nikon D3000S/Canon 7D comparison gave you last year. I bet if I tested resolution at low ISO the Canon would win; if I tested dynamic range, the Nikon would win. Yawn!

Posted on by tychay 2

Why dSLRs (and not pocket cameras)? [The entry kit dSLR Part 2]

(Article continued from part 1)

Bigger in photography means, faster, better, stronger (and more expensive).

Many people will say the only advantage of a digital SLR is that it gives you the flexibility of interchangeable lenses.

I think that’s bullshit.

If it was true, then the days of the dSLR are surely numbered—EVIL has arrived. EVIL, for those of you who don’t know, is an acronym so new, it doesn’t have a Wikipedia page yet. EVIL stands for “electronic viewfinder, interchangeable lens” and they are a new class of camera I’ll talk about another time. Suffice it to say, EVIL will not replace SLR photography—in the same manner that APS-C has not yet dethroned 35mm (much to my surprise). Besides, a lesser-performing EVIL camera costs nearly twice as much as the kits in this article.

I believe the biggest advantage can be found in its name: Single-Lens Reflex.

In order to have a single-lens design, in order to house a reflex mirror, the dSLR has to be big—and bigger, in this case, means faster, better, stronger (and more expensive).

Marie the shooter

Marie the shooter
Elite Cafe, Pacific Heights, San Francisco, California

Leica M8, Carl-Zeiss Biogon 2,8/25 ZM T*
1/45sec @ ƒ2.8, ISO160, 25mm (34mm)

This portrait of Marie and her new Nikon D5000 entry dSLR kit was taken by an APS-H camera, which sits between APS-C and “full frame” in size. Even though this is taken with a wide-angle lens (25mm), you can easily see she really pops from the background.

From your art classes, you may have learned that perspective helps a 2D image show the 3D dimensionality. In photography, another tool, in addition to perspective, is focus via depth-of-field. Focus helps draw the eye, through the visual clutter, to the subject. This tool is nearly non-existent in a pocket digital.

By the way, the lens used in this photo is the highest resolution lens in its class ever produced—the parts that are in focus are really quite sharp. Computed depth-of-field is about half a foot (20cm).

Continue reading about Sometimes bigger is better after the jump

Posted on by tychay 7