Cheaper alternative to rf 100-400 mm

[kolinbo1]

I am new to photography, and I will be trying myself out on birding photography. I found on various forums and threads that rf 100-400 mm mm is the good lens to start with, but I find $600 lens pretty expensive.

Hence, I was wondering if I can find any cheaper alternatives to rf100-600mm. I have a ef to rf adapter, and thus, I am open to trying ef lenses.

[Wandalynn]

It would be helpful to know what camera you're using. For a long lens like that, I don't think you're going to find anything used from a trustworthy source that's much less than the new price. I often buy used but only buy from Canon or Canon-authorized dealers. If you buy a used EF lens, you must make sure it will be compatible your camera--yes, they will physically fit on the adapter but the older models aren't necessarily compatible with the features of your camera--since you have an adapter you may already know this. For instance--and I'm just grabbing this out of my memory from when I was still buying EF lenses to use on my mirrorless--the older mark I of an EF lens may not be compatible whereas the mark II might be. What I mean by compatible is that the autofocus capability may not work or may not be as snappy as with an RF lens which was built to work with the R cameras. Another incompatibility I've experienced with older EF lenses on a new camera is the high-speed continuous shooting isn't available....maybe low speed or maybe only single shot. And for your birding photography, tracking may not be possible or not as capable as with an RF lens. Other features like focus bracketing most likely won't work if using an older EF model. If you buy from a reputable dealer you should be able to return a lens if it isn't working correctly with your camera. There are also resources online about lens compatibility. I recommend that you save up for an RF lens.

P.S. I'll add that the EF lenses I do still have are those that I don't necessarily need all features that bird photography requires. My EF lenses that I still have are the EF 24mm f/1.4 L II and the EF 8-15mm f/4 L fisheye zoom.

[p4pictures]

Realistically the best alternative to the RF 100-400mm would be the EF 100-400mm f/4.5-5.6L IS II USM, I have one and it works well on my mirrorless cameras using the Canon EF to EOS R adapter. I have not experienced any slowing of the drive speed and the lens focusses at least as fast as it did on my EOS 5D Mark IV. You might be able to find a used copy of this lens, but often it will be more expensive than the new RF 100-400mm. It is also much larger and heavier. 

[ebiggs1]

IMHO, 400mm is at the bottom of FL required for birding. This means again, IMHO, the 100mm to 300mm is almost useless. And it is why the 150-600mm super zooms are/were so popular. At this moment in time the Tamron SP 70-200mm f/2.8 Di VC USD G2 is the  best of that bunch and the one I would buy. I prefer the plain Canon ef to RF adapter.

Remember if money is a problem there is always the used market. However if you want everything to work as Canon designed it off brand EF lenses may not be able to do that. How much of that you need for birding is up to you.

[Tronhard]

Hi Kolin and welcome to the forum:
There is little point in us suggesting lenses unless we know a hard $value of what you can afford.  The problem is that long lenses are not cheap, as @Wandalyn and my other associates have pointed out, anything decent is liable to be more than you have the funds for.

What camera are you attaching this lens to?  Is it an R-series camera? 

If you are using an APS-C camera, such as the R7, R10, R50 or R100,  then any lens you get will deliver a narrow Field of View because the sensor does not record all that the lens projects, which is similar in effect to using a longer focal length lens.  This 'cropping effect' is thus often called the 'focal length multiplier' and, for Canon cameras, that multiplier factor is 1.6.  Thus, a 100-400mm lens attached to an APS-C body will deliver images that are Equivalent to those of a lens of 160-640mm on a full-frame camera.  That  is to your advantage when shooting at the telephoto focal range.

If you want to learn more about this, and I would encourage you to do so, then read the following article that you can download: I share it from my MS OneDrive as a Word document:
Equivalence: Sensor Size, Focal Length and Field of View 

100-400mm would be a minimum focal range, as my colleague Ernie suggested. However, as we seem to agree, a lens of 100-400mm is going to be outside your budget at the moment.  If you can let us know what camera and optics you currently have we can at least have a better idea of how you can proceed as you continue to save.

Since you admit you are new to photography, there is much more you can do in the meantime.  I would strongly encourage you to study the control of the exposure with the shutter speed, ISO and aperture.  This combination will offer many variations to get the correct exposure for your images, but what values you select will have a profound impact on the resultant image.  There is much to learn, and wildlife photography has the challenge that you have little control over either the conditions under which you will shoot, and a not necessarily cooperative subject.  Apart from studying photography techniques, you should also study the kinds of wildlife you will encounter - to give you an idea of their behaviour to anticipate a potential shot, but also for your own safety if they are sending signals of aggression.  You will also get a much deeper appreciation for the wildlife out there.