APS-C Format: Why and How to Get Started With A Crop Sensor Camera

Sony a6700 Camera, attached Tamron 18-300mm lens, Sony 50mm f/1.8 lens, and Meike 25mm f/1.8 lens

Situation: you have an older camera, maybe a 15+ year old DSLR, or you want to get your first interchangeable lens camera and have already begun researching brands and learning about things like the light triangle, different focal length lenses, and how to shoot in manual mode. In this case you have likely heard of APS-C sensor cameras. How do you know if APS-C is the right choice? And what camera and lenses do you need? If this sounds like you, you have come to the right place. In this article I will discuss why you should (and several reasons you shouldn't) invest in an APS-C camera, what level of APS-C camera you should invest in, and what lenses you should buy to get started depending upon your photography goals.

APS-C? What Even is That?

First off, what is an APS-C camera? For those who do not already know, APS-C (also known as a crop sensor) is a camera with a sensor that is approximately 66.6% the size of a full frame sensor. Crop sensors measure 23.5mm x 15.6mm, whereas full frame camera sensors that replicate 35mm film are 36mm x 24mm. The diagram below shows how they compare.

Approximate difference between APS-C and Full Frame Sensors (not to scale)

So, what does having a smaller sensor mean? Well, a smaller sensor does a number of things, but the three most important factors are: it affects low light performance, it changes the focal length and f-stop of the lenses you use, and it generally makes your gear smaller and lighter.

Less Light

A crop sensor camera is smaller and therefore does not collect as much light for a given aperture as a full frame sensor. This means that crop sensor cameras do not perform as well as a full frame in low light. So, does that mean you cannot use an APS-C in low light? Not at all! Crop sensors can still be used in low light, but with some considerations. Basically, you just need to compensate with longer shutter speeds, larger aperture lenses, or (where appropriate) a flash. The biggest drawbacks are a generally reduced amount of dynamic range and increased difficulty in situations where slowing down your shutter speed or using a flash isn't an option.

Increased Focal Length

When you put a lens on an APS-C camera, you need to multiply the focal length by 1.5 for Fujifilm, Nikon, Pentax and Sony, or 1.6 for Canon. This is called the "crop factor." This also applies to the f-number, so a 50mm f/1.8 on a Sony crop sensor camera would be equivalent to a 75mm f/2.7 on a full frame camera. This even applies to lenses designed for crop sensor cameras as lens manufacturers use full frame sensors as the standard against which they measure everything since they replicate 35mm film.

Smaller Size

A smaller sensor generally means your camera and your lenses will both be smaller as well. This makes them easier to travel or hike with and makes them cheaper than a full frame equivalent (where a FF equivalent exists). More affordable is always a good thing, but the drawback is that, because full frame is the industry standard, there isn't necessarily going to be a crop sensor version of a full frame lens. The current selection for the top camera brands is still pretty good, with the biggest holes in selection being specialty lenses and long zoom fast lenses. The good news here is that many full frame lenses can be used on an APS-C camera. This is especially true for third party lenses like Tamron or Sigma. As such, you will just have to pay the full frame lens price for the lens you want.

So, should you invest in an APS-C system?

The biggest draws for APS-C are the affordability of the camera bodies and lenses, the flexibility of the system, and, as mentioned above, the portability.

Affordability

Last year I purchased a Sony a6700. For the price of $1399 I got an autofocus system that is equivalent to the mid to high end Sony full frame cameras, dual native ISO settings, in-body image stabilization, and a flip out screen, all at half the price of an equivalent full frame model. This discounted nature for crop sensor cameras also carries through to the less sophisticated models; if you want fewer bells and whistles you can get what you want for much less than a full frame equivalent. For an enthusiast like me, getting a high-tech camera at a more affordable price point was a huge draw. I had a limited budget, and I wanted the high end features while still staying within my budget.

Jack-of-All-Trades

If you are like me and you want to try everything: landscape, astrophotography, macro, portraiture, wildlife, etc., then APS-C may be the best choice for you. This is because the benefits of the APS-C size, the crop factor and the smaller physical size of the gear, can make it more versatile than a full frame camera. For instance, the crop factor makes an APS-C camera better for macro photography than a full frame camera. This is because the crop factor makes it easier to fill your frame with a tiny subject. It also results in having a slightly deeper depth of field for a given aperture, so more of your subject is in focus.

The crop factor also means long distance shots are made even easier. A 300mm lens  on a crop sensor camera becomes equivalent to a 450mm lens on a full frame. This makes reaching out and getting those long range wildlife shots easier for cheaper. Meanwhile, taking a landscape photo on a tripod where you can adjust the shutter speed to get your ideal light level or taking family photos in bright daylight at the park is no harder on a crop sensor than a full frame. The day-to-day workload of your camera doesn't suffer because of the smaller sensor.

Travel Buddy

Lighter weight and smaller size means easier travel and more packability. This is especially true if you get a good zoom lens that covers your desired range of focal lengths. Tamron makes an 18mm-300mm lens that, while a little on the larger side, is still smaller and lighter than multiple lenses that might be needed to cover all that range. If you want a camera that travels well but still has good performance, APS-C is hard to beat.

So when should you not choose an APS-C system?

Well, as the saying goes, Jack-of-all-trades, master of none. If you are going all-in on astrophotography, macro, or professional portraiture, you will get more value by investing in a more specialized system. Also, if you want a truly pocketable camera you can throw in an already fully loaded backpack, there are better options.

Astrophotography has cameras designed to fit on telescopes and that will reach out further and better capture the colors of celestial bodies. Macro photographers will often go for a micro 4/3s system, as they are even smaller sensors which further increase the benefits of APS-C over full frame cameras. Additionally, some models, like the OM system cameras, have in-camera focus stacking which makes getting photos of small, heavily magnified subjects even easier. If you are wanting to be a wedding photographer or sports photographer, you need a camera that maximizes low light or high speed performance. Full frame cameras will always give you better performance in these high demand and low light situations where longer shutter speeds are just not an option. Also, full frame cameras are available in higher megapixel sizes than crop sensor cameras, so getting the absolute highest detail possible requires something other than an APS-C.

So, while an APS-C system is versatile, it doesn't stand up to other cameras designed for specific uses or larger sensor cameras where low-light and high speed are your constant companions. Lastly, if you are looking for a truly affordable, all-in-one camera that defines packability, companies like Canon, Nikon, and Sony are still making compact cameras that will suit you just fine.

You can also get a smart phone like the Google Pixel or iPhone with quality on-board cameras without adding any more size or weight to your planned packing. Can compact cameras or phone cameras compete with the picture quality of APS-C? No, of course not, but if all you are doing is making small prints or posting on Instagram, you don't need that much detail.

I Know I Want an APS-C Camera, Where Do I Start?

OK, so you've done the math and APS-C is right for you. What do you need most to get started? Well, if you buy a camera/lens combo, that kit lens can get you the basic photos of your family and trips without adding a lot of cost or size. Unfortunately, kit lenses will only take you so far, so once you know you want more you should start looking at lenses from your camera manufacturer as well as third party manufacturers. If you know right from the start that a kit lens will be a waste for you, consider buying the camera without a lens and spend the difference towards a more specific lens you know you will use.

Third party manufacturers are a great source for quality glass at a more affordable price. I have used Tamron, Meike, Rokinon and Sigma lenses and all of them make quality, affordable products. You can really get a great deal with these manufacturers if you are looking for a prime lens, especially if don't mind manual focus and aperture. I have a quality 25mm manual lens from Meike that only cost me $80.

Best All Around

Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD on a Sony NEX5-T

My pick for top lens with the most versatility is the Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD. At $600US it is a pricey lens for entry level photographers, however, I have taken pictures of all kinds in every lighting condition with it and, in my opinion, there is no better lens to cover everything. Like the APS-C sensor itself, it is a Jack-of-all-trades, so it doesn't handle low light as well as a faster lens and high-end prime lenses will produce noticeably sharper images, but for sheer versatility it really has no equal. The pictures below as well as the quail shot above were all taken with my Tamron 18-300mm. It is available for Sony, Nikon and Canon APS-C cameras.

If you want to spend less but still need a good all around lens, look for something like an 18-105mm or 28-70mm lens. Every manufacturer makes their own versions in these sizes and they will run half or less the cost of the 18-300mm Tamron. One of these lenses with your new camera can get you landscape, architecture, street photos, and even portraiture. Look for lenses with image stabilization to help you when you are shooting hand-held as this will also make them more versatile. If you need a cost break, look at second hand retailers like KEH or B&H to see if you can get a good used lens at a steal.

Low Light "Fast" Lenses

If you want a good low-light lens, consider buying a prime lens. Prime lenses are those that have a single focal length. Because of this, they are less expensive than zoom lenses and are more easily found with wider apertures. Look for something in f/1.8 or even f/1.4. If you are shooting landscape or street photography, look for one in the 12mm to 35mm range. These allow nice wide shots and if you choose one with manual focus, can be found new for less than $100. I have a Rokinon 12mm f/2.0 which I used for the aurora picture below, and I have a Meike lens which is a 25mm f/1.8 which only cost $80. It has taken some great landscape photos as well as star photos.

Astrophotography

Speaking of the stars, if you want to capture constellations, look for f/1.8 lenses in the 25mm to 50mm range. As I mentioned earlier, 50mm on a crop sensor camera gets you 75mm equivalent focal range. I found this to be the exact right size to photograph Orion on my APS-C cameras. Anything higher than 50mm will start cropping in too much for some constellations, such as Orion, so keep that in mind when choosing a lens. Anything less than 25mm I have found to make constellations too small. For Milky Way photos, 12mm to 25mm work best, especially since the lower focal lengths allow you to make your individual shots longer without getting star trails. Upwards of 15 to 30 seconds can be taken without noticeable trails on a 12mm lens. That said, if you want to buy just one lens for astrophotography, the 25mm to 50mm range is what I have found to produce great results and cover most situations using an APS-C camera.

Macro

If you want to try macro, consider starting with a manual focus lens like this 60mm f/2.8 lens I have which was also made by Meike. I have taken some great photos with it, and while it can be challenging not having autofocus, it is not a deal breaker by any means. If you want autofocus, look at getting a used lens as a brand new macro lens will likely cost you over $500. This is pricey if you are only wanting to try macro photography out for the first time, as these lenses are dedicated to macro photography. They can be used for portraits as well, but there are much better lenses for portraiture.

Portraits

Speaking of which, a nifty 50mm with f/1.8 will be your best friend for portraits. The wide aperture gives you a beautiful blurry background, or bokeh, and allows for better performance in low light. The fact that this lens can pull double duty as a constellation lens for astrophotography means it is a really great value. As such, I would recommend investing a bit more in a higher quality lens with autofocus and image stabilization, like my Sony - E 50mm F1.8 OSS Portrait Lens (SEL50F18/B). Normally running about $350, I have found it on sale often as it is a popular lens. Every manufacturer will have an equivalent nifty 50, so look for sales or used lenses on sites like KEH or B&H where you know the lens has been examined and graded. I even have a friend who uses a nifty 50 on his Nikon for semi-macro applications, so it is a truly versatile piece of glass. The last thing I will say about portraiture is that, if you have a smaller studio space you plan to use, the 50mm might be a little tight. To avoid being too close, you could consider a 25mm to 35mm lens. A 35mm lens with the crop factor I discussed earlier will be the closest to an actual full frame 50mm lens and won't require you to be as far back from your subject to get full body shots.

If Unsure, Borrow or Rent

Lastly, if you don't know what you want, find a place to rent or find a friend to borrow a lens or even a whole camera system. Doing this will help you determine exactly what will work best for your photos without making a purchase you will later regret.

So, What is The Takeaway?

If you want an interchangeable lens camera with a good selection of lenses, good performance in most situations, and will allow you to try a bit of everything, consider investing in an APS-C camera. The lens range and camera cost will allow you to "have it all" while still on a budget and without any major sacrifice. If at some point you decide you want to specialize in astrophotography or wedding photos, then make a switch then and get some money back by reselling your APS-C equipment. But, if you are like me, no one specialty will satisfy you, and so an APS-C camera with a range of lenses for every occasion will not only let you do it all, it will allow you to do so without investing so much you have to go hungry or homeless.