retina 5k 27 inch imacAntonio Villas-Boas/Tech Insider

Minutes after I booted up one of Apple’s upcoming new iMacs at work, I had a crowd of colleagues huddled around my desk.

The new iMac, an updated version of the one that launched about a year ago, has a high-resolution “5K” display, which means it can play so-called ultra high definition video. Images are so crisp and clear that no photo or written description can do it justice. You want to reach out and touch it. It's the kind of thing you have to see in person to truly appreciate.

That probably explains why so many of my colleagues were drawn to my desk when I loaded up an ultra HD video of wildlife in Costa Rica on the iMac. You can’t stop looking at this thing.

Apologies for the poor photo quality, but the look on everyone’s faces says it all:

Tech Insider staff looking at new Apple iMacCaroline Moss/Tech Insider

This week, both iMac models are getting updates. And that super-sharp screen is coming to the smaller model for the first time.

Here’s the rub:

The new 27-inch iMac has the same screen resolution as the model that launched last year. The only updates are a faster processor, other improved internal specs, and better color representation on the screen. (More on the color thing later.) From now on, all 27-inch iMacs will have a Retina display. It starts at $1,799.

The 21.5-inch iMac is getting a Retina display for the first time, but you’ll still have the option to buy one at normal resolution. Because the screen is smaller, it has a 4K resolution, which is still insanely sharp and detailed. (4K is the new standard for ultra HD.) It also has a faster processor and better guts inside compared to last year’s iMac. The 4K model of the 21.5-inch iMac starts at $1,499.

new retina imacsSkye Gould/Tech Insider

And finally, Apple is launching some new accessories to go with the iMac. It ships with a redesigned wireless keyboard and mouse with batteries you charge with a Lightning cable, the same cable iPhones use. There’s also a new wireless, rechargeable trackpad (sold separately, $129) that has a pressure sensitive surface. All the new accessories will also work with any Mac running El Capitan, the latest operating system that many Mac users can download for free.

You can get all that stuff starting this week. (Apple Stores will have the Retina iMacs on display starting Wednesday so you can see the screen for yourself). I’ve been using the 27-inch version of the updated iMac and there’s really nothing else like it. I couldn’t find a comparable Windows machine that came even close to matching the design, screen resolution, and overall internal specs of the new iMac. It’s in a class of its own.

The Screen

The real story here is the 21.5-inch Retina iMac. Over the years, Apple has slowly been adding high-resolution screens to all of its devices. The 21.5-inch iMac and MacBook Air were the only two holdouts until now. And $1,499 is a pretty good starting price for a computer with a built-in 4K screen.

Most computers, even those that have screens so sharp that you can’t see pixels, don’t have displays that can handle 4K video. It’s the kind of thing you don’t know you were missing out on until you try it. If you have a regular HD TV, think of the difference it made when you upgraded from standard definition. Going from regular HD to 4K is just like that. It’s a giant leap.

27 inch retina imacAntonio Villas-Boas/Tech Insider

It’s not just about resolution though. The new iMac screens can show color better too. Without getting too technical, the screen can interpret colors better and give you a closer representation of what the image looked like in real life. In geek speak: Apple extended the color gamut of the iMac screen. That means if you take photos with a DSLR or videos with a high-end camera, you’ll see a lot more color and detail when you import the files to the new iMac.

But the average person probably won’t notice. I had to look at side-by-side comparisons to really see what has changed. This feature is better for photo and video professionals, not necessarily regular users who just want to do some light editing of photos they took with their iPhone. Just know that you’re getting a really nice screen and that Apple took the extra step to make sure it keeps getting better. Nothing wrong with that.

Accessories

The new wireless keyboard, mouse, and trackpad are great upgrades too. The mouse and keyboard come with the iMac out of the box, and Apple will sell them separately if you want to use them with an older model. All the accessories are rechargeable, and Apple says you can get up to 30 days out of a single charge. You can also quickly charge the mouse and get a full day out of it after plugging it in for just two minutes.

new mac wireless keyboardAntonio Villas-Boas/Tech Insider

Other than the rechargeable batteries and slight design tweaks, the keyboard and mouse are mostly the same as before. It’s the wireless trackpad that got the biggest upgrade, and I prefer it over the mouse. It includes Force Touch, Apple's new feature that can tell how hard you click down and open up an extra layer of control when you click on something. For example, you can use Force Touch on a location in Apple Maps to bring up a window with more details.

It also has a nice, large surface, which gives you plenty of space to swipe around if you're using the larger iMac.

new mac wireless trackpadAntonio Villas-Boas/Tech Insider

But the trackpad’s price can be a bit hard to swallow: $129 is a big ask for something that doesn’t add much more functionality than your mouse already has. I imagine most people will be fine with the included wireless mouse.

Conclusion

I saw the original Retina iMac on Apple’s campus about a year ago but only got a few fleeting minutes with it in a room full of crowded journalists. That wasn’t enough time to really appreciate how awesome its screen is. 

After spending a few days with it hands on, I realized the screen does more than just make things look pretty. It makes the entire experience richer. And now that you can get the same experience for a few hundred bucks cheaper with the 21.5-inch iMac.

If you need a new desktop computer, this is the one you should look at first.