[automorphism]

I would absolutely get this lens if I were on a tight budget. I think it will even better with the new canon R7 because of the price of the combo. For good light birds, 800mm is a whole lot of reach. That being said, I find f/7.1 to be a little limiting even during cloudy weather or forest shade, so for generalist birding, there are other way better lenses. But for someone who wants to add a little birding into their mix, especially with slower moving birds like ducks and geese sitting on rocks, this is a pretty decent option and far better than those old mirror lenses.

[repaap]

I would absolutely get this lens if I were on a tight budget. I think it will even better with the new canon R7 because of the price of the combo. For good light birds, 800mm is a whole lot of reach. That being said, I find f/7.1 to be a little limiting even during cloudy weather or forest shade, so for generalist birding, there are other way better lenses. But for someone who wants to add a little birding into their mix, especially with slower moving birds like ducks and geese sitting on rocks, this is a pretty decent option and far better than those old mirror lenses.

Yes, f 7,1 is little limiting. Let alone f11 which is the lower and upper limit with this lens as it is fixed.

[3by2]

My god it's ugly though. Like someone made a lens out of a soil pipe.

[Rondec]

It would be pretty much unusable around here in winter or in the evening hours. The reason for wider apertures isn't for shallow depth of field, but merely to let more light in in situations where you can't bump your iso up more (or don't want to).

[biz-engineer]

F/11 is not a big deal on full frame for this sort of lens.

When I read this it reminds me my "theoretical" sentences in forums when I didn't have experience shooting wildlife.
Shooting bears at dusk (from a hide) two years ago, I brought my 70-200 f2.8 and my 150-450 , and I used the 70-200 @ 200 wide open because it was too dark for f5.6
Given the experience I have now in wildlife photography, usually around sunrise and sunset times, I would never make the beginner's mistake to buy a long lens that's limited to f11.
But, I think a lot of beginners will buy those f11 lenses, gain some experience and then sell them to get an better 500 f4 or 600 f4 lens, I think that's the goal of canon: creating a step stone to get people into buying the longer / faster more experience lenses. As I can see the comments, Canon's strategy to get more people into wildlife photography should work well.

In the same league are the newly released mirror lenses: https://petapixel.com/2021/02/16/russian-optical-company-shvabe-unveils-four-new-mirror-lenses/
There is the Rubinar 1000mm f10 and the 500 f8 macro, light weight, inexpensive.

[Wasp]

Do keep in mind that this lens works with those new-fangled mirrorless wonders. An aperture of f/11 is really not a problem. The viewfinder screen just goes lighter to compensate for the relatively dark image from the lens. Also, those mirrorless wonders have the latest in sensor technology - high ISO is not a problem either.

[lesmore49]

\
But, I think a lot of beginners will buy those f11 lenses, gain some experience and then sell them to get an better 500 f4 or 600 f4 lens, I think that's the goal of canon: creating a step stone to get people into buying the longer / faster more experience lenses. As I can see the comments, Canon's strategy to get more people into wildlife photography should work well.

I think that is likely. There have been two separate reports on the local news about how the number of people in my province have got into birdwatching during covid has increased significantly.

The other report was an interview with a manager of a local camera store who indicated that sales of cameras and telephoto, along with other lenses such as macro, portrait, wide angle, etc. lenses have really done well during covid, as more people have got into photography, or have rekindled their interest in photography due to covid confinement.

The emphasis seemed to be on people buying cameras and telephoto lenses, if I recall .

I don't recall when this Canon 800 mm lens was first introduced, or how long it would take to design and produce such a lens, but I wonder if Canon designed it after covid hit ? A small company like Pentax would take longer to go through the design and production process, but Canon I would say would be considerably quicker at going through this process and able to bring a lens to market, quickly.

In the end I don't know. Just idle speculation on my part.

[normhead]

Do keep in mind that this lens works with those new-fangled mirrorless wonders. An aperture of f/11 is really not a problem. The viewfinder screen just goes lighter to compensate for the relatively dark image from the lens. Also, those mirrorless wonders have the latest in sensor technology - high ISO is not a problem either.

When someone shows me one of the "Mirrorless wonders " <derisive snort>, produces as good better or better images at 3200 ISO than any other camera does 100-400 ISO I'll be on board. The fact that one camera might be better at 3200 ISO than another, also at 3200 ISO, doesn't mean either image is all that good compared to what the camera capable of. This lens removes the possibility of taking the best image the camera is capable of. But it may be good for those who just want something. Or are we now going to argue that a 3200 ISO image on an R6 can be just as good as one taken at 100 ISO? This is an amateur lens, for amateur shooters. My buddy with the Nikon 600 ƒ4 and 1.4 tc will blow this out of the water in every way imaginable. Personally, I'd rather pass on the type of image possible with this lens, although in perfect conditions I'm sure it's theoretically possible to get great images with it. But the probabilities of getting great images with it are seriously reduced compared to more expensive glass. Once you've lost a few images because all you had was this lens, you'll start to see the foolishness.. most great opportunities only come once.

But for someone who just wants something to show they were there, it will be adequate. They may have to settle for head shots on some images, or no shots in others. And their 3200 ISO image won't be as good as an image taken with a lens that opened couple stops more and can get down 400 ISO. People need to reflect n the fact that base ISO is base ISO because it's the best possible image and further away you are from base ISO, the further you are from your best image, for that camera. Maybe you can't get to base ISO with your gear, but some guys will. . But hey. Everyone picks the parameters that suits their style and their budget. This is nice, but hardly earth shattering. A DA*560 with a TC would be a stop better but a lot more money. It's selling point is it's price. Period. That being said, it looks like a great way to try out long lens photography without committing a fortune to the experiment. And for some it will be more than they ever need or wanted.

Despite what people might think, shooting 3200 ISO when you could be shooting 400 ISO is never the best solution, on any camera. But anything is better than nothing. And maybe you'll get lucky, maybe you'll produce some fantastic images with it... stranger things have happened.

The learning curve for those of us who have shot thousands of long glass images leads us away from small aperture lenses, although we have one Nikon shooter here who has ditched his fast glass for 150-600 type lenses But 150-600 type lenses are "fast glass" compared to this guy. This lens is probably the smallest aperture you could use to give you chance at something decent. Someone spent some time figuring out where the bottom of the barrel was.

PS
After all that I look out my window and I could use it. Bright winter sun, snow reflected light making it extremely bought., my feeders are far enough away 800mm would be worth it. I could set up in my window and not have to sit out in a cold blind. It may be bottom of the barrel, but it would still have its days. If it was here right now I'd dig it out and use it.

[Rondec]

Do keep in mind that this lens works with those new-fangled mirrorless wonders. An aperture of f/11 is really not a problem. The viewfinder screen just goes lighter to compensate for the relatively dark image from the lens. Also, those mirrorless wonders have the latest in sensor technology - high ISO is not a problem either.

The issue isn't the viewfinder. It is the declining image quality that you get as you go over iso 1600, even on full frame cameras. For birds, even on tree limbs you need a shutter speed of what, 1/50 second, for decently sharp images? I just find image quality declining as you push the iso up and there really has been minimal improvement in sensors with regard to high iso performance over the last five or six years.

[Ian Stuart Forsyth]

I like the posted images....stationary birds in direct sun. But I could post a thousand images that couldn't have been taken with it. Here's one

It is particular odd that you picked this image, If we compare it to the FF 800ƒ11 the amount of light difference between the 2 settings is less than a stop of light gathering.
I know many cropped body users that would be please to have a 500mm ƒ7.3 lens. Heck this lens is not much slower than the 55-300 4.5-6.3 with the 800 ƒ 11 only being less than a 1/2 a stop slower but as it can reaching to 500 (Cropped) over the 55-300 that would be a bonus from many.

How many here would like to see a low budget 500mm ƒ7.3 lens for the K3mrk3?
Probably many of the same people that are happy with the 55-300 6.3

---------- Post added 02-21-2021 at 11:38 PM ----------

Diffraction and CA should be measured as a fraction of the number of pixels affected.

Why ?
When diffraction happens before the light hits the sensor.

Looking at it based on pixels size will give you some wrong notion that there is some magical diffraction point related to the pixel size. The true of the matter a 36mp well into diffraction at F16 will capture more detail than a 12mp at its sharpest f-stop

If we look at where diffraction happens at the pixel level what does it really tell us and how does it relate to photography ?

[normhead]

I'm surprised you have to ask but here we go.

There is always diffraction and CA in every image image past the diffraction limit. In lenses that have less than a pixel the odd colours from diffraction and CA tend to be overpowered by the light coming straight through the lens, as the diffraction and CA are always weaker than direct light. Until the diffraction becomes larger than a pixel it won't soften the edges. Once it becomes larger than a pixel it can soften the edges of the object photographed. That would be Klaus' from Optical Limits interpretation. The link I posted earlier in the thread suggested the 2 or 3 pixels is OK. But I'm going with Klaus' opinion since he actually measures the effects of diffraction with all the lenses he tests.

But to understand this all you have to do is ask yourself, what would be the effect of sending soft unfocussed light at the sensor during an exposure. Diffraction is a pattern of light created when the wave nature of light interacts with the aperture blades. Because of the wave characteristics the light hits the blades and scatters at odd angles. The smaller the aperture, the higher percentage of the light entering the lens is scattered. So diffraction becomes more pronounced as the aperture opening becomes smaller. However as pointed out in the thread above, long lenses are less affected because their apertures are bigger than wider lenses for the same ƒ-stop. So it's possible this lens (or any lens this long won't be much affected by diffraction even at ƒ11.

The charts where you can see the measured results that confirm these things are further up the charts.

Essentially if you understand Aperture, you know that resolution increases from wide open on a good lens very quickly. A good lens will hit maximum sharpness by ƒ2.8 or ƒ4. Because at it's level of sharpness, a bit of diffraction causes loss of resolution sooner, but normally, when you stop down the lens gets sharper until it hits the diffraction limit. For APS-c and FF it's between 5.6 and ƒ8. For my 1 inch sensor with it's much smaller pixels it's between ƒ2.8 and ƒ4.

If you think back to your grade 13 physics, if you're as old as I am, you actually did several experiments that demonstrate diffraction, both with light, and a simulation using marbles.

The other caveat here for photographers is that for the best lenses their maximum resolution comes sooner. If you go through the charts at Optical Limits you'll find every lens with a rep for great sharpness experiences it's resolution a wider ƒ stop, than the average lens which is between ƒ5.6 and ƒ8.

Here's an example Pentax 50 2.8 macro lens. Because of it's resolution it's diffraction limited by ƒ4.


The DA 50 1..8 on the other hand it's it's max resolution at ƒ5.6


Sharpness is affected by two things, making the aperture smaller increases resolution until you reach the diffraction limit (you can find diagrams on line explaining why.) Once the diffraction limit is reached even though the lens without diffraction would be sharper, the dulling effect of diffraction makes them softer. When you shut down your aperture you are always playing those two effects off one against the other.

You can see from chart of the DA 300 ƒ4


And yet it is buried by the DA 70 2.4 (not even a star lens)


So while the longer lenses are diffraction limited, in my limited search for examples, long glass would seem to be much softer than shorter lenses to begin with so possibly the diffraction , having less resolution to start with diffraction has less of an effect.

You only have to look at the charts of a typical 150-600 to see how these lenses perform at 600 mm. Or anywhere really.


I would expect this 800 to be similar.

Anyway, I'm having a discussion with myself here. Enough for now.

[repaap]

I think that this lens is not for serious birding. To me it looks like very good alternative for a scope you look the birds with and you don't have to put anything between the telescope and the camera. And it is entrylevel price for a big telelens to try it out. OR when you travel to somewhere and don't want(are not allowed) to lug a huge lens in airplane for daytime walkabouts at the coastline when at holiday. This is where this kind of thing would be very good.


Then diffaction won't matter, then poor f stop don't matter, then rainy day for whole week won't matter since you will just sit in and drink beer whole week and possibly you get one chance for going out with it. It won't matter and possibly you'll get a nice photo of something to look at when you get back home. Fair enough.

in fact I could be one this thing is made for, other than it should be WR and a bit faster. even f/8. So it is not me. but it coud be.

[normhead]

I think most of us would use it occasionally if it were already in the cupboard. The question is do we want to spend a grand to acquire it, just to have it sit around for days on end.

[repaap]

I think most of us would use it occasionally if it were already in the cupboard. The question is do we want to spend a grand to acquire it, just to have it sit around for days on end.

This is true and that is why I actually said that this is quite special lens even if it is cheap. Special in the way that you’ll probably end with having it sitting in drawer for a good day. It is not alone at there but in that class it is one of most expensive ones..

[normhead]

How many here would like to see a low budget 500mm ƒ7.3 lens for the K3mrk3?
Probably many of the same people that are happy with the 55-300 6.3

$1600 for my Tammy 300 2.8, with the 1.7 AF adapter, 510 4.5. So, not me. I own the 55-300 PLM and it's appeal is it fits in a small size camera bag, with room for the 21 ltd, and it's class leading IQ. There is nothing you can do to make this 800mm lens in any way competitive in portability and probably in IQ either. So not me there either.) You've gone Zero for 2. Almost 9/10 sharpness with a weight 442 grams. My guess is most people interested in a 442 gram smaller lens that fits in a small camera bag, on the camera, are not going to be interested in a 1200 gram really long lens. They are for different purposes. It's small for 800mm, but hardly small.

What we need here are some folks who actually bought the lens.

That being said, it looks impressive. Ken Rockwell's review is very complimentary.