Are full-frame cameras worth the cost?

So your Christmas bonus has come in, and it's not a subscription to the jelly of the month club. Or maybe you just want to start 2021 off on a better foot, and treat yourself to a new camera system. What to choose? There are so many on the market. Asking the internet for help is the kiss of death - you'll get more suggestions than there is cameras to choose from. I'm not going to offer camera suggestions, but in this article, I'm going to help with one of the big questions. Which size sensor should I be considering in my next camera?

Anyone who's been interested in photography over the past 10 years is likely aware that digital SLR cameras have been historically manufactured with multiple imaging sensor sizes. While there is a large assortment of the exact dimensions and aspect ratios, they generally fall into 2 categories: cropped sensor, and full frame. The smaller sized 'cropped sensor' cameras have been the more popular type due to their lower cost, but recently full frame cameras have become far more common. When making a new camera purchase, which one do you go for? As the saying goes "bigger is better!" Or is it?

A Nikon D850 with a full frame sensor is shown on the left. On the right is a Nikon D3500 with a cropped sensor. Both cameras are to scale to each other.

The inspiration for this article stemmed from some advice I recently gave a friend. He had asked me for my thoughts on his next underwater camera setup, and I offered my opinions. During the course of our discussion, we talked about a variety of SLR and mirrorless camera options, and I ultimately recommended one particular cropped sensor camera. He was surprised I didn’t recommend the more expensive 'bigger brother' of this model which featured a full-frame sensor and asked me “why?” 

My short answer to him was, “It’s not worth it.” I went on to explain that for the underwater hobbyist photographer, I don't feel there is added value in a full-frame camera setup. To best explain my answer, I feel it’s necessary to lay a little groundwork for the laypersons among us. 

One of these shots was taken with the full-frame Nikon D850. The other was taken with a cropped sensor Nikon Z50. Can you tell the difference?

As we touched upon in the beginning, the term “cropped sensor” is slang for a digital camera with an APS-C sized imaging sensor. APS-C is short for Advanced Photo System, Type-C. This is a discontinued film format created by Eastman Kodak in 1996, and denoted a film size of 24mm. With the introduction of commercially available digital cameras in the early 2000’s, technology limited the maximum practical and cost-effective size of the sensor to around 26mm. As they were similar in size to the APS-C, these new sensors took the same name. Later, as production techniques advanced, manufacturers were able to increase the size of the sensor to a size similar of traditional 35mm film, while keeping a reasonable retail price.

Over the years, Nikon, Canon, Sony, and Olympus have all developed slightly different dimensions and aspect ratios of the APS-C. And there's no shortage of names, abbreviations or slang used to denote one camera sensor from the other. DX, FX, 4:3rds, EF, EF-S, etc.

None of this is terribly important, and for the sake of simplicity in this article, we will use the terms ‘cropped’ for a 26mm sensor (measured diagonally,) and ‘full frame’ for a 35mm sensor. While camera manufacturers today seem to be churning out more and more full frame camera bodies, the cropped sensor camera is still very much prevalent in the marketplace. 

So why might a photographer choose one over the other? Let’s first look at full-frame cameras. These sensors being larger, means they have more surface area, which allows them to gather more light. More light gathering capability generally means better image quality, particularly in low-light environments. Larger sensors also have better depth of field control, which can be  important for a topside photographer. The downsides of full-frame cameras are they are larger, heavier and far more expensive. Not only the camera bodies are more costly, but also the lenses they shoot. 

Examining a cropped sensor camera, we find they tend to be smaller, weigh less, and are less expensive. While cropped sensor cameras can mostly utilize the same expensive lenses a full frame camera would shoot, they are more commonly paired with the less expensive and lighter weight 'cropped' lenses. Those who have researched the topic may have also heard of an advantage called ‘crop factor.’ We’ll come back to this in a moment.

As we just mentioned, there's not only a difference in the sensor size, but the lenses these different cameras can shoot. The next explanation covers the lenses themselves, and this is where many people get confused. We will begin by discussing the method in which lenses are differentiated, and that is called focal length. Focal length is not to be confused with the distance or range at which the lens focuses on an object, rather it’s the measurement in millimeters of the distance between the camera sensor and the optical center of the lens. 

This is a simple illustration of a lens and DSLR. Note the lens elements are not accurately represented. In this example, we have a 60mm lens. 60 mm is the distance between the optical center and the sensor plane of the camera. This results in an angle of view of approximately 34 degrees.

In this illustration, the focal length is now 35mm. Note the field of view is now wider, at approximately 56 degrees.

The second thing to understand is there are lenses made for full frame cameras, and there are lenses made for cropped sensor cameras. These are different to best accommodate the different sizes of sensors between the 2 cameras. 

With cropped sensor lenses, you’ll often hear the term “35mm equivalent.” For example, the Nikon AF-S 85mm lens has a 35 mm equivalent of 127mm. This simply means, that if a lens of the same angle of view were used on a 35mm camera, the focal length would be 127mm. The term became popular with the earliest digital cameras and the new cropped sensor lenses that sprang up as a result. Photographers were so accustomed to the 35mm film standard with focal lengths, the new focal lengths of the cropped sensor lenses were confusing. They needed a standard they could relate to, and the “35mm equivalent” was born. As a casual shooter, you don't need to worry about this.

With geometry being what it is, a lens on a cropped sensor camera lens might have the same focal length as the lens used on a full frame camera, but in the illustration below, you can see how the angle of view is in fact, different. 

The focal distances in both these examples is 60mm. However the lens on the left is intended for full frame sensors, and the area it projects onto the sensor plane is larger, resulting in a wider angle of view. The lens on the right is intended for the smaller sized cropped sensors, and the angle of view is narrower. This is what's known as the 'crop factor.'

Lastly, it’s important to understand that these lenses are sometimes physically interchangeable between cropped sensor and full frame cameras, but this doesn’t mean they will work. You can use a full-frame lens on a cropped sensor camera. The angle will be different, and if you are using a telephoto lens, or macro lens, you’ll get an advantage known as the ‘crop factor’ that we spoke about earlier. This simply means that your angle of view will be even narrower due to the smaller sensor. The net effect when using macro, is that you’ll essentially get increased magnification from the lens. 

You cannot however, use cropped sensor lenses on a full frame camera. The lens will fit the camera body, however when you try to use it, you'll find some degree of vignetting in your image. This is because the lens is optimized for the smaller 26 mm sensor, and is not projecting the image onto the full frame sensor completely. 

In both these examples we have a cropped sensor lens. The camera on the left is cropped sensor, and the cone of light from the lens covers the sensor completely. The camera on the right is a full frame camera, and note how the cone of light from the lens does not cover the sensor completely. This would result in vignetting, and is why cropped sensor lenses cannot be used on full frame cameras.

Now, many full frame cameras have an option to use what’s called “cropped mode,” and that is precisely for this exact scenario. If you have a cropped sensor lens you wish to use on a full frame camera, enabling this setting will restrict the area of the sensor the camera uses to a cropped equivalent, at the cost of quality and image size. 

How does this apply to underwater shooting? 

So as we now know, full frame cameras have a larger sensor, which will require larger lenses, which in turn (for wide angle photography) require larger dome ports. The dome (more specifically the air-water boundary created by the dome,) actually becomes an optical element in the chain between the subject and the camera. Many of you probably already know that a specific diameter and curvature of a dome, as well as a specific distance from the dome to the camera sensor plane are required in order to achieve a sharp wide angle image underwater. This becomes even more critical when we use a full-frame camera.

Full frame camera bodies, lenses, and domes are more expensive than their cropped sensor counterparts. And I mean, a lot more expensive. To help illustrate this, I went online to Reef Photo & Video's website and built two underwater camera systems. One is a cropped sensor camera, and the other is full-frame. 

I chose the Nikon D850 and compared it to the Nikon Z50. It’s not a perfect comparison, as the Z-50 is a mirrorless camera, and uses a different lens system, however it does have a 26mm cropped sensor. The main reason I chose to compare these two is because I currently have access to both, and have been using them regularly. 

Nikon Z50 setup cost (cropped sensor)

• Camera body

• 16-50 lens

• Housing

• Flat port

• WWL-C

• Mount

• Lens gear

$5,400 (rounded)

Nikon D850 setup cost (full frame sensor)

• Camera body

• 16-35 lens

• Housing

• 8.5” Dome port

• Extension ring

• Zoom gear

$9,800 (rounded)

Comparing the 2 systems, we have a difference of $4,400. Now with underwater photography there are a large combination of lenses and ports we could select from to alter these figures. I tried to establish a pair of camera systems that had the equivalent field of view, with the least expense. 

No matter how we configure them, the fact remains, there will be a difference in cost of several thousand dollars at minimum. So the question is, will you see this return in image quality? Will the D850 take a photo that is $4,400 better than the Z50? If you sell photos, will you earn $4,400 more in stock sales over the lifespan of your camera?

For most of us, probably not. My own personal photography is used for social media, the Divetech website, and the occasional print I will hang in my home. Sometimes the Cayman Department of Tourism will use my photos, and some have them have been printed in very large formats. Lately with COVID-19 keeping Cayman's borders firmly shut, Divetech has been selling prints of my photos as a means to generate revenue. For all of the photos in these applications, my cropped sensor camera is more than up to the task. However, you can be the judge. Take a look at Divetech's print gallery and see if you can determine which photos were taken with a cropped sensor camera and which ones were taken with a full frame camera. If you're still not convinced, take our quiz at the bottom of the page.

Here are the biggest reasons I can think of to shoot a full-frame camera:

• If you shoot a lot in very low light situations. Cave photographers, or perhaps someone who takes a lot of photos in deep, dark environments.

• If you are a professional photographer - meaning someone who earns their living taking photographs, you may consider a full-frame camera for your topside shooting, but it's not essential. I know of one great photographer whose living is earned by selling photographs he's taken using nothing but cropped sensor cameras.

• Portrait photographers should absolutely use full-frame for the increased bokeh effect.

• Pro videographers, who actually sell their footage to media and production houses. In my experience, these places tend to shun video taken from cropped sensor cameras, no matter how good the quality may be.

• If you have extra cash burning a hole in their pocket, and want bragging rights.

But for the rest of us - casual hobbyist shooters who shoot underwater for fun, facebook likes, or even for those who publish photos, books and earn side income from their photography - my advice is it the full-frame system probably not worth it. Not only are these systems more expensive, but they are larger and more difficult to travel with. 

The biggest variable in any photograph is the person behind the camera. I've seen many photographers with expensive full-frame cameras who just turn out horrible photos. I've also seen very talented photographers make wonderful images with inexpensive point and shoot cameras. A quality camera is merely a tool to make art. An expensive camera can make the artist’s job easier, but it’s not essential. Someone knowledgeable about photography can make do with whatever they have at their disposal. Ironically, the first photograph I ever sold to a magazine was taken with a Canon S90 point and shoot system. It’s why you may have heard the saying “The best camera is the one you have with you.’

So for these reasons, I typically will recommend cropped sensor cameras when asked. Save the money, and take photo lessons with it. Your return for your dollar will be much improved.

Have questions or want more advice on camera selection? Send me an email to tony@divetech.com.

Happy diving!