How does the display quality of the 21.5-Inch and 27-Inch "Late 2009" Aluminum iMac models compare to previous Aluminum iMac models?

Please note that the "Late 2009" Aluminum iMac models were replaced by the "Mid-2010" models on July 27, 2010. However, the displays used by the "Mid-2010" line (as well as the current "Mid-2011" and "Late 2011" models) are quite similar.

Review a comparison of the displays used by each of the Aluminum iMac models, and it is evident that the "Late 2009" Aluminum iMac models -- the iMac "Core 2 Duo" 3.06 21.5-Inch (Late 2009), "Core 2 Duo" 3.06 27-Inch (Late 2009), and "Core i5" 2.66 27-Inch (Late 2009) -- have higher quality displays than those used by earlier models.

The "Late 2009" 21.5-Inch display is 8-bit with brightness of 320 cd/m2, a contrast ratio of 1000:1, and a viewable angle of 178 degrees horizontally and vertically. By comparison, the 20-Inch display in the iMac "Core 2 Duo" 2.66 20" (Early 2009) is a considerably lower quality 6-bit display with brightness of 290 cd/m2, an 800:1 contrast ratio, and a viewable angle of a mere 160 degrees horizontally and vertically.

The "Late 2009" 27-Inch display is 8-bit with brightness of 375 cd/m2, and like the smaller display, has a contrast ratio of 1000:1 and a viewable angle of 178 degrees horizontally and vertically. The display in the 24-Inch "Early 2009" models is 8-bit with brightness of 385 cd/m2, a contrast ratio of 750:1, and a viewable angle of 178 degrees horizontally and vertically. This is significantly better than the display in the 20-Inch model sold at the same time. However, "Late 2009" displays are LED-backlit as well, whereas previous displays are not and this makes the "Late 2009" displays look considerably brighter.

Reviewer Opinions

Although it certainly is helpful to have a solid understanding of "raw" specs, it also is worthwhile to peruse a sampling of reviewer opinions obtained through "real world" use.

The typically balanced Consumer Reports loved the display in both the 21.5-Inch and 27-Inch models:

The displays on these iMacs are gorgeous. Colors rendered by the LED backlighting are deep and true, though only slightly more so than on the previous iMac. The 21 ½-inch is brighter than the previous 24-inch model. The 27-inch is even brighter: At its maximum setting, it's a vivid 400 nits -- brighter than any other computer display we've tested. And its LED backlight comes up to full brightness instantly, and has longer expected service life than the usual CCFL backlights. The display has a very wide viewing angle, both horizontally and vertically, making it good for collaborating with others on graphic design and gaming.

The Windows-centric PCMag also liked the 27-Inch display:

The 27-inch screen is LED backlit and is bright and clear. HD videos look great on the iMac, and the system is powerful enough to play 1080p videos smoothly in Quicktime, iTunes, or on the Web like on YouTube. The screen is viewable from a wide angle, a plus when more than one person is watching.

Gizmodo found the 27-Inch display to be a bit "too big" for comfort:

The contrast is welcome; even my new 13-inch MacBook Pro looks yellowed and washed out next to it. But at this pixel density, which is sharper than my notebook, it's almost too sharp, requiring me to sit closer than I would ordinarily do with a 27 inch display. I like the feeling of crispness -- 16% crisper than the last generation. But my eyes feel like the pictures are being delivered by a land shark holding a laser pointer straight into my corneas, and I can feel the strain within minutes. I would have to jack up as many font sizes as possible or sit as close as I do to my MacBook to make it work for long long periods of time.

The industry-standard MacWorld took issue with the reflective qualities of the "glossy" display, noting more of an issue with multiple people viewing the display than PCMag:

Looking at the new iMacs at different angles, I had a difficult time noticing any color shifting. When compared side-by-side against the previous iMacs, the 20-inch iMac screen looks like a mess, while the new iMac screens maintained their color integrity.

There's one major issue with the screen that, for many, is a deal-breaker: the glass on the display and its glossy effect. The glossy effect makes colors pop and blacks deep and rich, but you can see your reflection in the glass. When using the iMac as a desktop computer, I've learned how to see past the glare and reflections, but many others cannot develop such tolerance -- and I'm not saying you should. Glare is a problem if you're in a group gathered around the 27-inch iMac that's being used as an HDTV. In fact, because of the glare, you might reconsider using the 27-inch iMac as a HDTV.

Display Quality Summary

It is hoped that the above reviewer opinions may be useful, but ultimately, the only opinion that truly matters is your own. You may decide that the 27-Inch display is just right or "too big". You may like the "richer" colors the glossy display provides or find the "glare" intolerable. If you have any doubts, you may wish to check out the "Late 2009" iMac models in person prior to purchase.

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