Real World Comparison of Lumix 100-300 vs 100-400mm Lens

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There are a few lenses in the Micro Four Thirds world that are really geared towards wildlife photography. Two of them are the budget Panasonic Lumix 100-300mm II f4-5.6, and the more expensive Panasonic Leica 100-400mm f4-6.3.

They have the full frame equivalent focal lengths of 200-600mm, and 200-800mm respectively. Quite nice for wildlife lenses in small packages! Their f-stops have the same light gathering abilities as a full frame of those specs would, only that the background blur (bokeh) would be less.

So how do these compare with each other? Is the Leica really that much better than the Lumix? Is the extra zoom worth it? Which one should you invest in?

I’ve owned and used both the Lumix 100-300mm, and the Leica 100-400mm lenses for a while now, and finally gave each a good enough real world test to be able to do this comparison.

By “real world test” I mean I used them walking around as I normally would to take pictures of birds and animals at a distance, which is the primary purpose of these lenses. I did not use a tripod, because it’s so very hard to do that with wildlife that moves around quickly, and I honestly almost never use one. It also shows just how good the IBIS (In Body Image Stabilization) really is on these cameras!

Note: I didn’t share any examples here of pictures taken on the short end (100mm) or in between, because honestly, when it comes down to it you use these lenses for their max zoom. I did take some test pictures with them at 100mm and the results were almost indistinguishable, they were that similar!

Cameras used

For this review I used both a Panasonic Lumix G85 and the smaller Lumix GX85. These cameras both have the same 16 megapixel sensors, and almost all of the same features so I felt they made good comparisons images. I had a lens on each, and I did swap the lenses around to test them on both cameras in case there’d be any notable differences–there weren’t.

I tried my best to get photos that were as equal to one another as possible with both cameras/lenses. Obviously with birds and wildlife that was pretty difficult, because they move so often, but I got lucky a few times and felt these tests were good enough. They’re not the best photographs by any means; but I believe they demonstrate and answer the questions I had for both lenses.

All the photos below come from RAW files I minimally processed in Lightroom(only adjusting the exposure and/or contrast in post). No noise reduction or sharpening unless otherwise noted.

You can see the original 100% sized images of all below in my test images gallery.

300mm vs 400mm

Is that extra bit of zoom really worth it?

With the FF equivalence of 600mm vs 800, I always thought that it would be a big difference. But turns out it’s not quite as much as I thought it would be.

Here are a few examples. The left hand column using the 100-300mm @ 300mm, the right being the 100-400mm @ 400mm:

Examples of zoom with larger subjects

For subjects that are medium to large in the frame, you can probably crop any of the above from the 100-300mm and get a decent enough photo I think.

Examples of zoom difference for smaller subjects

For subjects that would be small in your frame to begin with, then there should be a bigger gain in detail at 800mm. You also get slightly more bokeh(blurred background effect), but is it really enough to justify the 100-400 lens?

Detail Resolution and Sharpness

Let’s do some pixel peeping! Normally, I wouldn’t care about pixels being slightly less sharp or smudgy looking when viewing them at 100%. Because for most uses of sharing photos on social media you’re not looking that close. However, when you want to crop in on a little bird that’s sitting on a branch in the far distance, it starts to matter!

Another thing is, long zoom telephoto lenses require a lot of light. Even during the day with the sun out. If you’re in the woods or around some shade, you’re going to be loosing it, and your shutter speed will go down, or your ISO will go up, even with your lens set on the widest aperture. So you always want to be on the lowest f-stop number you can.

Shooting wide open at 400mm f6.3 , the Leica 100-400 looks good! The 100-300mm at f5.6 on the other hand, is not as sharp. It gets a little smudgy around the edges. You need to up it to f6.3 or 7.1 to get a comparable result to the 400mm wide open which means you’re loosing more light with the 300mm.

Below are some examples of the details picked up by both lenses. These are 100% crops of the images I posted above.

As you can see in the above, there is an increase in detail with the 400mm just by virtue of it zooming in a bit more, even when the ISO jumped up on the deer and the cat images.

Ok so we definitely get more detail being zoomed in more. But how do the different apertures compare in regards to sharpness? What settings should you try and keep them on?

This little chipmunk stayed pretty still thankfully, just chirping at me while I snapped a few dozen photos 🙂

Here are some 100% crop comparisons of f-stops from the above image:

As you can see going from f5.6 to 6.3 and 7.1 did help on the 300mm. I don’t see a whole lot of difference between those two, so would probably keep it at f6.3 most of the time to not loose another stop of light.

On the 400mm there is a slight increase in sharpness at f7.1, but not by a lot. I’d feel good keeping it at 6.3!

Post Process Sharpening

Ok, so maybe you feel that the 100-300 is good enough for you. Can the details be boosted in post processing to get a similar result to the 100-400? Let’s find out…

I used the latest ON1 Photo Raw 2022 NoNoise AI tools for these. Which worked really well! Better than the results I got in Lightroom even.

First up we have the 100-300mm(right column are the sharpened images). As you can see there is a benefit to doing some sharpening on these, most noticeable on the fur around the edges.

And the results from the 100-400mm….wow, what an increase in detail! Just goes to show you when you have more detail to begin with, these algorithms can do a lot more and really make things pop. Of course you do have to be careful it doesn’t get too over-sharpened-this is as far as I’d push them.

Image Stabilization

Image stabilization is mostly dependent on the camera you’re using.

Both cameras I used claim a 5 stop increase to image stabilization with Dual I.S. 2 on the Leica 100-400mm, as long as you have updated firmware.

If you have the latest Olympus OM-D E-M1 Mark III, it claims 7 stops on it’s own! I haven’t tried it, but that sounds pretty impressive and should be even more stable in your hands.

At any rate, the stabilization worked very well on both cameras. I did think I noticed a slight advantage on the 100-400mm, which should be the Dual IS 2 kicking in. So despite its weight and longer reach, it did just as good if not better than the 100-300.

Usage & Handling

The Lumix 100-300mm is lighter, smaller, and feels better on these cameras. It weighs 1.14 lb (520g). The body seems to be made out of plastic, but doesn’t feel too cheap either. And the rubber grip on the zoom ring is a nice touch.

The Leica 100-400mm weighs over 1lb more at 2.17 lb(985g), but it’s body is metal and feels much more solid and professional. Holding both lenses, the 400mm definitely has extra heft to it both in hand and on the camera body.

That being said, I thought the 400mm might get too heavy carrying around, and I wouldn’t want to just throw it in my backpack on a day hike for the chance I might use it later on, but…it’s not that big of a deal to tell you the truth. I feel like if I have the space in my pack and/or don’t mind walking around with the 100-300 lens, then I also don’t mind walking around with the 100-400mm. It has never been a problem so far.

Another positive thing about the 100-300 is that the zoom rotation ring is much, much smoother. The 100-400mm feels like it gets a bit stuck, and it’s hard to rotate the zoom to a set focal length. Other users have also complained about this, but it sounds like not all models have it as bad as others. The copy I have does tend to stick unfortunately 🙁

A plus of the 100-400 is that it has a closer focusing distance. I noticed this while trying to get some closeups of insects in the garden. I got as close as I could, and because of that focus distance I was able to get a larger image of the subject from the 100-400–not just because of the increased zoom. It worked at all focal lengths.

Both lenses are weather sealed, which is always a great feature to have just in case. You can take them to the beach and not worry about sand or a splash of water, or getting rained on.

Final Thoughts

So…I have both of these lenses currently. My intent was always to keep one and sell the other, because I just don’t need them both. Since purchasing the 100-400mm, I honestly haven’t used the 100-300 at all, because the 100-400 is better quality, and I haven’t minded carrying it around. But I still do really like the size of the 100-300mm way more! And that’s what the Micro Four Thirds system is all about–smaller lenses!

Even though the 100-400mm is overall better, since getting it, my pictures did NOT immediately get better. I did NOT notice tons of image quality improvements…in fact, if I just look at my best “real world” photos and compare them, I wouldn’t be able to tell them apart 9/10 times. Why? Because what’s most important for wildlife photo details is that you get as close as you can. The bigger the image, the more detail, the sharper and better it looks. And of course the overall look and feel: composition, color, light, and subject matter that you captured, means even more for a good photo.

Little bird, taken with the Leica 100-400mm @ 400mm, f6.3, 1/640, ISO 250

In the end, the most important thing is that you’re taking great pictures that you like. No matter the camera or lens(although they can help!). I’ve taken tons of pictures that I’m very happy with using the 100-300mm Lumix. So much so that looking back on them all, it’s not easy to decide which lens to keep!

Gray Catbird, taken with Lumix 100-300mm II @ 246mm, f7.1, 1/640, ISO 640

One other note, I did in the past use version 1 of the 100-300mm lens. Personally I didn’t noticed any image quality differences, I mainly upgraded for the added weather resistance of the version 2 lens. If you don’t need that, you can save yourself some money and get the Panasonic Lumix 100-300mm I.

Robin, taken with the 100-300mm I @ 300mm, f5.6, 1/800, ISO 1250

So, here are some final questions to ask yourself when making a decision between these 2 lenses:

  1. Are you on a budget? Get the 100-300mm II. Tight budget? 100-300mm I and avoid any rain or dusty conditions. Don’t forget you can always sharpen in post processing.
  2. Are you really serious about wildlife photography? Then go with the 100-400mm. Maybe even the Olympus 300mm f4.0 if you’ve got the money and don’t care about having a zoom.
  3. Are you just going to take this out on occasion, for backyard bird photos, pictures at the local park by the lake, etc? Then the 100-300mm is probably enough for you.

You can see more examples of photos taken with various lenses in my wildlife photo gallery.

Have you used either of these lenses? Or maybe even the new Olympus 100-400mm? Share your thoughts below in the comments if you have any experiences or details to add!

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