Transferring from a bridge camera, I've really struggled to find any info for what you actually need for a wildlife photography. From what little I've gathered, most seem to recommend a cropped-sensor and a 400mm lens. Any longer lens would probably destroy my budget. But, I'm really at a loss as to what this would actually work for. The kind of DSLR I'm looking for is a 16mp, and yet for wildlife photos many seem to recommend >18mp, so you can crop your images. I'm at a loss to find when you'd actually need to do this though: for example, most pictures I take are probably at a range of 10-70 meters, and generally (on 12x optical zoom, which I know doesn't really transfer over to mm but I thought I'd say it) I can get my subject taking up almost the entire frame, which is the kind of photo I like.

But, I'm not sure whether a 400mm (~600mm with APS-C I guess) would actually be able to do this, at those long ranges, without cropping (which, with less megapixels would reduce my image quality, therefore voiding me wanting to get a DSLR). I've seen a lot of photos taken with a 400mm, but most of these don't say the distance shot at, and the cameras have many megapixels.

All in all, I'm just after some advice for people who do relatively budget wildlife photography with a lens like this, and what they'd say about how good it is at long ranges, etc. I keep seeing things that make me wonder if longer-distance photography just puts too much of a whole in your pocket. Thanks for reading, appreciate any advice :)

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    \$\begingroup\$ Which bridge camera have you been using? You are right that the "12x zoom" cannot be compared to mm, but there should be specifications available online that allow for a direct comparison. You mention the Canon SX150 IS in your other question. Apparently that camera's zoom should be a 28-336mm "full frame equivalent". A 400mm lens would then have more reach than that on a full frame camera, and almost double the reach on APS-C. \$\endgroup\$
    – Steadybox
    Commented Jan 20 at 15:04
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    \$\begingroup\$ A sort of facetious comment, but are you shooting elephants or humming birds? \$\endgroup\$
    – Peter M
    Commented Jan 20 at 15:38
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    \$\begingroup\$ No, there's no such thing as a long-enough lens for wildlife photography. \$\endgroup\$
    – Mark
    Commented Jan 22 at 8:20
  • \$\begingroup\$ Note that budget zooms are often not as good when zoomed in as far as they will go. \$\endgroup\$ Commented Jan 22 at 19:37
  • \$\begingroup\$ Consider renting gear to "try before you buy". Also consider upping your budget if possible - it's not always possible of course, but in photography it often happens that "you get what you pay for". \$\endgroup\$
    – osullic
    Commented Jan 24 at 0:57

9 Answers 9


Your current camera is the Canon SX 150 IS... which has a tiny sensor (1/2.3) and a lens with an equivalent recorded FOV of 28-336mm on FF. Any increase in either aspect will improve your results; and probably significantly.

Ignore the megapixel aspect... your camera's sensor has a resolution of 14.1 MP, but the lens is nowhere near up to that quality. It actually only resolves a maximum of 5.9MP; and only 4MP at ~MTF 50.

From the imaging resources review: enter image description here

And similar will be true with larger sensors of high MP. But as the pixels get larger it is easier for the lens to resolve to that level... i.e. it is possible to record closer to the sensor's resolution/rating with high quality lenses. So even if the larger sensor is of the same resolution, and cropped to a lower resolution in terms of MP; the actual recorded/remaining resolution in terms of detail/sharpness is quite likely to be higher.

Everything is a compromise... I insist on using high resolution (46MP Z9/D850) full frame cameras with high quality lenses in the 400-600mm range (e.g 400 f/2.8); but it comes at a high cost. And sometimes the results are not significantly better than using lesser equipment would generate. But when conditions allow, and I do my part, I can get outstanding results that stand up to 400% crops rather well... that kind of quality/resolution I don't actually have much need/use for most of the time. This was actually taken using the Sigma 60-600mm lens and it still has more resolution/detail than needed...

enter image description here

And for that reason I also have/use a 1" sensor with a 70-300 lens (14mp, 189-810mm equiv), and with good light the results can be more than acceptable for the requirement... especially for online/social media use. Just one example; I have many.

enter image description here

I also have a camera with a 1/2.3 sensor and zoom lens... I would not use that for anything particularly important/critical.

All of that just goes back to the first paragraph... any increase in sensor size or lens quality/FL will be a notable benefit. For you, M4/3 or APS would probably be the sweet spot. I would also pay more attention to the camera's performance in terms of AF tracking, frame rate, etc; rather than sensor size/MP.


Answering from personal experience: I have an APS-C Camera (Canon 70D) with a Sigma 120-400mm F/4-5.6. It takes a while to get decent shots. Don't underestimate the bulk of the camera+lens, and the difficulty to just frame something in a lens with a small field of view.

Also, focal length is important, but the longer it is, the faster the exposure should be (the image stabilization has its limits). Between 400mm and 600mm, you need to increase the shutter speed by 1.5, and so find half a stop of aperture, while in practice, that 600mm lens you are probably dreaming about is half a stop slower than a 400mm (f/63. v.s. f/5.6) instead of being half a stop faster (600mm f/4 lenses exist but they are heavy on credit card and in the bag). So the "consumer" 600mm requires either a very sunny day or a very sensitive camera.

Furthermore, the focusing systems of DSLR cameras normally require a f/5.6 lens, so f/6.3 lenses are pushing it ("pro" cameras will work to f/8) and your autofocus will lack accuracy exactly when you need it the most.

A $20 ghillie suit and good approach techniques will take you closer to your target than a $2000 lens.

  • \$\begingroup\$ A bit of personal experience that concurs with what you're saying: I use an OM-1 with their 40-150 f/2.8 pro (300mm ff equiv) lens, and while the reach of adding the 2x tele to get 600mm equiv is very nice in theory, the teleconverter degrades autofocus performance enough that I have far more misses; it's almost better to leave it off and crop. \$\endgroup\$ Commented Jan 21 at 19:32
  • \$\begingroup\$ @CharlesDuffy I have a 1.4x extender for my lens, that makes it a 900mm equivalent (400 x 1.6 crop factor + 1.4x extender) but also a f/8 lens and I have to use manual focus. But even on a decent tripod+gimbal head it is hardly manageable. \$\endgroup\$
    – xenoid
    Commented Jan 21 at 21:00

The idea about wildlife is: focal length is never enough. So maybe you should reconsider using DSLR and switch to Micro FourThirds format where you can find quite good cameras. And more important you can find very good tele lens like Olympus M.Zuiko Digital ED 100-400 mm F5.0-6.3 IS which will have effective focal length of 200 to 800 mm, compared to similar lens on APS-C camera with 150 to 600 mm. And the price of above lens is twice as cheap (compared to Canon 100-400 Mark II)

P.S. Forget about the zoom, this is not so important in DSLRs, mirrorless world. Also zoom ratio can't be translated (directly) in focal length.

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    \$\begingroup\$ Don't forget, you can also use the MC14 1.4 or MC20 2x teleconverter with that lens, although you lose a few stops. \$\endgroup\$ Commented Jan 22 at 13:20
  • \$\begingroup\$ @spikey_richie specifically you lose 1 stop with 1.4x or 2 stops with 2x. No matter which system or brand you choose. \$\endgroup\$ Commented Jan 22 at 20:11

You need to define several things.

What is enough? Is wildlife photography an elephant or a bird?

But more important questions could be. As you have some previous experiences with it, how close you have been normally to your subject? What is the size of your subject, and what size do you expect from your photos?

But those are things that you can only answer yourself.

Now for more "objective" tangible things, the factors you can technically explore are:

  1. Focal length
  2. Sensor size
  3. Mpx count

3. Starting from the last one. Mpx. In your other question, you say you would have a 12Mpx camera... Why not a 24Mpx that is a really common Mpx count? Twice the Mpx count does not mean a 200% increase in size, but "only" 142% more or less. But that is significant.

(I updated the image with a 16Mpx size)

enter image description here

2. Crop factor. If you are willing to sacrifice the benefits of full frame, such as noise or bokeh, you probably will do fine with this 1.6 increase.

enter image description here

1. Focal length Probably this one is the one bothering you. You are wondering if a 600mm lens is enough and a 400mm not.

More or less, the gain in size is similar to the two previous cases.

enter image description here

So in order to determine if those increases are "enough" define the size of the subject you want, the distances you can get, and the final pixel size you need.

You could use a calculator like this: https://www.pointsinfocus.com/tools/depth-of-field-and-equivalent-lens-calculator/

Using a Canon Crop sensor, with a 400mm lens at 20mts the size of the animal you can take to cover all the frame is 1.1m. A baby deer?

enter image description here

Now, go back to the Mpx. You can have a photo of a baby deer of 12Mpx (or 16) or 24Mpx.


We choose lens focal length based on subject matter and the size of the camera. Your camera is an APS-C (Advanced Photo System – Classic format). The digital sensor for this camera is a rectangle measuring 16mm height by 24mm length. The corner-to-corner measurement of this rectangle is 30mm. Mounting a 30mm lens is deemed the “normal” focal length for this format. If you mount a lens with a focal length 70% of “normal” or shorter (20mm or shorter), such a lash up is considered wide-angle. Mounting a lens twice “normal” (60mm) or longer is considered the realm of telephoto. Since 30mm is considered “normal” mounting a 400mm lens exhibits 400 ÷ 30 = 13X more magnification. In other words, a distant bird imaged with a 30mm yields a tiny image. Mount a 400mm telephoto and the image of the bird is rendered 13X larger. As a rule-of-thumb, a 400mm or 500mm telephoto is considered quire satisfactory when imagining wildlife.


There are many things to consider and mixed up units and babble words for easy preys...

Pick some cameras, rent them, try them, decide.
Reading further may help deciding where to start ruling some choices straight out and shortening they tryout period.

Look up this page on digitalcameraworld. It shows a relation between focal length (in mm) and sensor size (in mm), and view angle. The view angle is critical for you because it defines how far from the object you have to be so it covers the portion of scene you want. If you want to crunch numbers the tangent of half the angle equals to the width divided by the distance.

The camera sensor size and resolution seems to be the defining parameters but they are, actually the last ones to be taken in consideration.

The critical parameters are sensor noise and lens so-called speed, more to it later.

We shall start fom answering most crucial questions:

  1. How fast is your target about to move?
  2. How dark the scene is to be expected?

Answer to those questions define the lens you are looking for in term of its "speed". This property is defined in F-stop units like F3.5, F1.8, F8 and it describes how wide the lens' aperture can open. In other words it describes how much light can pass through the lens when aperture is wide open. The lower value the better. How is the speed value derived and how to calculate with it is way beuond the scope of this answer.
The faster your target moves and the darker the scene you expect, the lower F-values (faster lens) you are looking for.

The answers also define what sensor you are looking for in terms of sensitivity and noise. To get the picture bright enough you need to get enough light to the sensor or brighten the image artificially - multiply all the values by some ammount. You can clealy see that artificial brightening increase the noise. If you want to bring more light to the sensor you either need to open the apreture or expose the sensor for longer time. And here we are directly in the core of the questions.

Now we know what angles of view we are aiming for and we broadly have idea how fast the lens should be (as fast as buget allows, of course! no joking).

We can now move back to the diagrams on digitalcameraworld and check the lens prices for the common sensor sizes. Again, if you want to crunch number you can look for exposure equation - it's a function of shutter speed, aperture, sensitivity and scene brightness.

While you are checking the lenses you can also check the camera bodies for their ISO sensitivity. The higher sensitivity it allows (at noise acceptable for you) the easier you can go on the lens speed.

This is all but theory so far and we all know, theory is grey, green is the tree of life.

Pick couple of builds from different camera manufacturers (Canon, Nikon, Sony, Panasonic, Konica-Minolta, Pentax,...) lens manufacturers ([camera brand], Sigma, Zeiss, Tamron,...) and body types (DSLR, mirrorless,...) and sensor sizes (3/4, APS-C, fullframe, 6cm, ...) and keep the build within your budget limit times 1.2 - 1.4. Trust me, you will end up over-spending sooner or later, better to accept it sooner than later. Do not cross out second-hand gear! You can save quite a lot by sacrificing the feel of opening the not-yet-opened seals.

Here you can start thinking about sensor resolution, connectivity and other factors, but they doesn't matter that much.

You have your picks now and you narrowed the pool in, say, 6-10 options.

Rent one or two picks for a weekend and go out shooting (with your current gear too). If you are to shooting birds you ca pretend they are there and shoot the backgrounds instead. The aim is to get your hand on the cameras, try them out, push your limits with them. And write notes about it. How do you feel about them, how easy it is to operate them... Then rent another pick... You may realize you want something slightly different, so change it.

Then you will end up with a table of YOUR assessments and prices. And this table is the one to decide on, because it is YOU taking the pictures, not anyone of US and I'm sure OUR table will be different from YOURS.


As @Mark stated in the comments of the original posting, you'll never have a lens long enough for wildlife.

You don't mention what sort of critters you're trying to shoot. You don't mention the model of the camera you're using right now which would help in knowing the full-frame equivalent focal length range.

That said....
I capture wildlife shots using a crop sensor body (1.5x). My lens choices are generally 18-140 mm vacation lens, 100 mm macro, and a 200-500 mm telephoto. The wildlife I shoot range from small insects to large animals.

Part of shooting wildlife is stalking techniques. Chasing after animals is useless unless they are tame. Setting up a blind (in your house, tent, bushes, behind a rock, ...) and letting the wildlife come to you is mostly what I do.
Know the habits of the wildlife. A general rule is hide your eyes as wildlife keys off of eyes. The camera body is a great way of hiding your eyes when using the viewfinder. Understand the dangers, both geography and if the wildlife can do you harm. I don't go after grizzly bears and keep a respectful distance from moose. I won't go close to an adult rattlesnake, but will get close to a baby rattler because they are more docile, even though their bite is usually worse than an adult rattler.

The following shots are uncropped samples of a variety of wildlife I have come across.
The squirrel is skittish, thus requires a moderate shooting distance for the size of the critter. There was no place to hide since this is open tundra.
The musk ox required a long lens. Not knowing the habits of the musk ox, I kept a reasonable distance along with a tree I could hide behind in case it charged. I was armed with bear spray.
The caribou came to within 15 metres and the vacation lens was more than enough to shoot them. They didn't mind the clicking of the shutter since it sounds like the clicking of their tendons when they walk (part of knowing your animal). I was behind a bush but they could clearly see me. However, my eyes were hidden by the camera. Caribou are fright animals, thus won't attack unless you corner them or are in rut.
The baby rattlesnake is about knowing the animal. Baby rattlers are docile, but their bite is usually uncontrolled which means they will give you a full dose of venom if you get bitten. The camera was about 0.33 metres away and I kept a barrier between me and the snake. A breath of air will get its tongue flickering. With adult rattlesnakes, I like to keep at least 2 metres distance.

enter image description here

Depending on your skills and patience (waiting for wildlife come to you) you can use a moderate focal length lens. However, 400 to 600 mm lenses will give you more freedom in capturing wildlife shots.

Another thing to watch out for, long shots can have heat wave mess up the image if you are shooting over hot surfaces like gravel or asphalt.


It is important to think about how you will display the photos and how hard you are willing to work to get them. I had been using a bridge camera with a maximum effective focal length of 600mm for some years and heard about the Nikon P900 which goes to 2000mm. Yes, it is a small sensor and noisy. It takes practice to point the camera accurately enough and hold it steady enough even though the image stabilization is amazing. One of my first photos was a great horned owl, which come out a dusk. Handheld sitting down the shutter speed was 1/80. The photo looks great on a computer display, but you wouldn't blow it up to 16" for the wall. I post to iNaturalist where you want a photo clear enough for identification but don't need the big enlargement. It means I can go for a walk in the woods and not spend hours getting closer to the bird. I have since moved on to the P1000. I have a nice mirrorless APS-C body and rented the two 150-600s thinking the more and better pixels would compensate for the zoom being "only" 1000mm effective. I sent them back, but the problem with renting is that you don't get much experience before you have to make up your mind. 400mm on an APS-C sensor can be quite good, especially for birds that you aren't so far from.

I wouldn't worry so much about cropping, again depending on what you will do with the photos. I also try to fill the frame in camera, but the problem is that you often cut off parts of the image because you aren't pointing accurately enough. This is even more of a problem at the focal lengths I am talking about. I have started trying to keep some room around the subject unless it is quite still and crop later. Most of these long zooms are weakest at the maximum focal length, so reducing the focal length and cropping is not as much of a loss as you might expect.


Sigma 150-600mm may be a good place to start without selling body parts. You can always hire a lens to try it out before investing.


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