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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21 thoughts on “Real World Comparison of Lumix 100-300 vs 100-400mm Lens”

  1. I am eager to buy a 100-300, but am not entirely sure whether to go for the first or second edition. For me, what’s most important is image quality. I think that weather sealing might be important. Even though I don’t go out in the rain, maybe weather sealing might prevent dust from getting inside over time? I can get a used copy of the first version for about $315, a used second version for about $410, and the newest for just under $500, but I am not entirely sure about which to get.

    • So I did have both the 100-300 I and 100-300 II at one point, and you really couldn’t tell a difference in image quality. I believe officially they are the same in that department. I imagine the weather sealing would help, but how much dust would get in overtime that it matters, I don’t know. If you’re really worried about image quality you might want to save up more and go for the 100-400mm, which does show a difference in image quality, although it’s not huge as I’ve explained here.

  2. Hi,
    Question for Video on tripod would you go with gh5s,gh6 100-300,100-400 or maybe with my S5 FF 150-600 sigma lens?
    Eventually with S5ii if they ad any decent animal detect
    For slow mostly?

    • I don’t have much experience with video, but if it’s on a tripod I think you should go with what has the best autofocus. But again if the subject isn’t moving much and you have time to focus that’s not that big of a deal either. The best autofocus is currently on the OM System(formally Olympus) OM-1 camera. You won’t get better than that. The Lumix GH5, 6 series cameras are mostly known for their excellent image stabilization and video settings. Take a look at all the features you need most and pick from there.

  3. Thank you. I managed some great bird shots with the GX 80/85 and the much smaller 45-175 lumix lens. I then bought the 100-300 II but found that the GX80 was too slow to focus especially on birds in flight. So I bought the G9 camera and this transformed the 100-300 lens as the camera has super fast focussing and lots more options to help capture birds – I found the camera’s size is perfect for the 100-300. I am interested in the 100-400 but not convinced. As you say will the potential for extra sharpness overcome the weight downside. Thanks for your review

    I have held onto the GX80 as its a great camera. The 12-60 leica lens works brilliantly with it making it my goto package for general photography

    • Thanks for your input on the G9 preforming better! Yes birds in flight are difficult with the G85/x85. I plan to eventually get a newer camera with better autofocus. I know the best out there right now is the OMD OM-1 flagship model. It made significant improvements to autofocus. But even the Lumix G9 like you mentioned or the Olympus OM-D E-M1 Mark iii are great choices.

      • G9 is a good choice, I think use more money for staying in wild. If you understand the subject and behavior then you are able to capture more better images. A wildlife photographer use 2 or 3 lens. Only animals and birds are not nature, think about overall kgs. On your shoulder. Wheather is also a challenge. I think 100-300mm is best.

      • I own the Panasonic G9 and have always struggled with its continuous autofocus for birds in flight. The EM1 Mark 3 is noticeably better and the OM1 much better in this regard.

  4. Excellent review: thank you! I will try getting the 100-300 for a « test drive » and see how it feels. I’m more of a wide angle photographer but sometimes you need a telephoto, so the 100-300 makes a lot of sense. I usually shoot with Olympus Pro glass (12-100 or 8-25), so I need to try before I buy.

    • You’re welcome, glad the review could help you! If you’re used to shooting with Pro quality lenses, you might be a bit disappointed in the quality of the 100-300. It’s not going to be as sharp or fast of course. But…it does get you really good telephoto reach for a good price! Personally I don’t mind the compromise and take it for what it is.

  5. 100-300 is an ok lens. Its biggest advantage is its compact size. But i think that sooner or later i ll buy the 100-400 for the extra reach and sharpness. I ll keep em both though. I wonder how those 2 lenses work with Olympus cameras.

    • Yes I hope to get an Olympus camera eventually to try them out on it. I suspect they’ll work just fine however; Olympus has more in-body stabilization than Panasonic with their newer EM5 and EM1 cameras.

      • I don’t think IBIS will matter as much in the long telephoto ranges, where the angle of view can get below 5°. IBIS is great for wide angle and landscapes and wider portraits (<50mm), but I don't see a great improvement with it above 100mm on the G9. OIS is way more important as you get into the longer focal lengths.

  6. I have the 100-300 version 2 and I am quite happy with it but on the other hand have never tried the 100-400 or the P Leica 50-200 for that matter.
    Yes, sometimes in some situations the lens feels a bit soft past some point after 250mm. But I bought the lens for extra reach shotting landscapes and as an inexpensive way to move towards birds and wildlife. I figured if it turned out that I really didn’t get into it (birds e.g.) then having the 100-300 made more sense than the 100-400.
    Also, I really don’t want a lens more than 500g on my camera. Otherwise the point of smaller size and weight with MFT just sort of disappears. The 100-300 is just so different from all of my other MFT lenses that if I haven’t been out with it for some time, it takes a little time to get used to it.

    (AmI the only one with a comment here? Or are comments just for the “owner of the site”?)

    • Yes it is probably the best inexpensive wildlife lenses out there to have, for its size & weight especially! I also have not tried the 50-200mm, but I feel it would be too short for much wildlife. And thanks for your comments-no, none are hidden, you’re just the first one to post! 🙂

    • I’m getting ready to purchase the 100-400. I’m concerned about the stiffness of the lens is that goin to be a problem or will I adjust? I also have the original 100-300 it is a nice lens but I can’t
      hand hold it at 300mm I’m 72. I believe the new 100-300 has some stabilization

      • Well the stiffness is annoying if you are trying to get a precise focal length. I mostly always use the lens at the long end, 400mm, so it’s not a big deal to me. I have never found that I “missed a shot” because of the stiffness. Also, I have read many reviews on this lens and some people say their copy isn’t stiff, so you might get lucky. One other thing is that Olympus has a 100-400mm version which you might want to look into as well.
        If you have a problem hand holding the 100-300mm then I don’t think you’ll be able to hand hold the 100-400 which is heavier and bigger. I do feel that the stabilization is a bit better in it, but not by a huge amount. It also depends on what camera body you’re using.


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