500mm vs 600mm

[AnnetteJane]

Hi folks.

My current kit is a Nikon Z8 with a 500pf: However, like many people, I am always on the search for more reach. The simplest (and cheapest) option would be to buy a 1.4TC to use with my 500pf, but I'm also curious about the 180-600. My concern with the latter option is that it's "only" 100mm longer, and still won't give me the equivalent to the 500 + 1.4TC. The upside is that it will be f6.3, rather than a f8. Tbh, I don't need the zoom, so that seems a bit of a waste, but I can't afford the 600pf without selling the 500pf, and even then it's a bit of a stretch to make up the difference.

I live in British Columbia and therefore low light shooting is a consideration, so I'm a little skeptical on how much I would actually use a f8 lens (500 + TC).

My questions are:

1. Is there much benefit going from 500mm to 600mm?
2. Am I right in assuming that the AF of the 600pf would outperform the 500 + TC?
3. If I sold a kidney to replace my 500pf, is the 600pf a worthy replacement?

For reference, my subject matter preferences are fur > feathers, although I love shooting raptors (ospreys, eagles, owls etc). I'm not a birder and don't photograph songbirds, typically.

Sorry for the rambling musings and thanks for looking and input.

I'm debating along similar lines. I have the 500 5.6 pf. that I use with my Z9. I like it a lot. I would like more reach. Is it feasible or practical to get the 600 6.3 ? The 6.3 is bothersome, I'd rather something that works better in low light but I know 5.6 to 6.3 isn't that bad, better than the teleconverter. I DID get a teleconverter but I hate putting the thing on and off. I do regret the teleconverter purchase.
I am not considering the 100-600 due to weight. I have loved the lightness of the 500 5.6 pf.
Another part of me says maybe just keep the 500 and be happy with what I have.
I'd love to get the 600 :/
800 seems a bit cumbersome and once again, that little bit heavier might make me need something to help steady it. I love being able to easily hand hold. Plus the 600 travels easier than the 800.

 

[Ken Miracle]

I'm debating along similar lines. I have the 500 5.6 pf. that I use with my Z9. I like it a lot. I would like more reach. Is it feasible or practical to get the 600 6.3 ? The 6.3 is bothersome, I'd rather something that works better in low light but I know 5.6 to 6.3 isn't that bad, better than the teleconverter. I DID get a teleconverter but I hate putting the thing on and off. I do regret the teleconverter purchase.
I am not considering the 100-600 due to weight. I have loved the lightness of the 500 5.6 pf.
Another part of me says maybe just keep the 500 and be happy with what I have.
I'd love to get the 600 :/
800 seems a bit cumbersome and once again, that little bit heavier might make me need something to help steady it. I love being able to easily hand hold. Plus the 600 travels easier than the 800.

If you do not need the reach of the Z800mm f/6.3pf the Z600mm f/6.3 pf is excellent. I own and use both.

I owned the f mount 500mm f/5.6 pf. until I moved to all Z in June 2022 it was a very good lens the Z600 is better all around and you are correct there is really no practical difference between f/5.6 and f/6.3.

The Z600 pf is 11" long compared to 9.3 for the 500pf but that does not include the FTZ adaptor.
Weight is almost identical and with the ftz adaptor the 500pf is actually heavier.
500pf 1460 grams + FTZ 127.5 grams = 1587.5 grams
Z600pf 1470 grams

 

[bleirer]

I'm debating along similar lines. I have the 500 5.6 pf. that I use with my Z9. I like it a lot. I would like more reach. Is it feasible or practical to get the 600 6.3 ? The 6.3 is bothersome, I'd rather something that works better in low light but I know 5.6 to 6.3 isn't that bad, better than the teleconverter. I DID get a teleconverter but I hate putting the thing on and off. I do regret the teleconverter purchase.
I am not considering the 100-600 due to weight. I have loved the lightness of the 500 5.6 pf.
Another part of me says maybe just keep the 500 and be happy with what I have.
I'd love to get the 600 :/
800 seems a bit cumbersome and once again, that little bit heavier might make me need something to help steady it. I love being able to easily hand hold. Plus the 600 travels easier than the 800.

I don't think the 1/3 stop between 5.6 and 6.3 makes much difference. If it's ISO 1600 on one it would be ISO 2000 on the other.

 

[AnnetteJane]

Think I'm sold on the 600 6.3.
Just have to wait till I can afford it now This wild life stuff gets expensive. Have to pay off the overland trailer and new laptops first :/ But I know what lens I want next... 600 6.3 pf
I started with a tamron 200-600 and traded for a Nikon 200-500 for "better glass". Then I went to the 500 and was very much in love with the lightness. Miss the 600 reach. I liked the zoom a lot but the prime is definitely faster and I prefer the prime. Except when I need a zoom. My second body is a Z7 and I tend to change lenses before using the Z7. My second favorite lens is the 70-200 2.8 for when it's getting darker and closer subjects.
I'm considering selling my second body but I take it "just in case".

 

[Ever]

Think I'm sold on the 600 6.3.
Just have to wait till I can afford it now This wild life stuff gets expensive. Have to pay off the overland trailer and new laptops first :/ But I know what lens I want next... 600 6.3 pf
I started with a tamron 200-600 and traded for a Nikon 200-500 for "better glass". Then I went to the 500 and was very much in love with the lightness. Miss the 600 reach. I liked the zoom a lot but the prime is definitely faster and I prefer the prime. Except when I need a zoom. My second body is a Z7 and I tend to change lenses before using the Z7. My second favorite lens is the 70-200 2.8 for when it's getting darker and closer subjects.
I'm considering selling my second body but I take it "just in case".

I think we're on a similar upgrade path.

I started with a D500 and 200-500. Swapped the 200-500 for the 500pf. Fast forward a bit, and I have a Z8 arriving today

I don't see any changes for a long time. But I'm already observing possible next-steps, of course. Guessing it's swapping the 500pf for the Z600pf. Or if I win the lottery, a 400TC + 800pf

 

[Doomrider74]

I think we're on a similar upgrade path.

I started with a D500 and 200-500. Swapped the 200-500 for the 500pf. Fast forward a bit, and I have a Z8 arriving today

I don't see any changes for a long time. But I'm already observing possible next-steps, of course. Guessing it's swapping the 500pf for the Z600pf. Or if I win the lottery, a 400TC + 800pf

I think we are sharing the same path . I have to pay off my Z8 before I get the Z600pf, unfortunately.

 

[wotan1]

I'm debating along similar lines. I have the 500 5.6 pf. that I use with my Z9. I like it a lot. I would like more reach. Is it feasible or practical to get the 600 6.3 ? The 6.3 is bothersome, I'd rather something that works better in low light but I know 5.6 to 6.3 isn't that bad, better than the teleconverter. I DID get a teleconverter but I hate putting the thing on and off. I do regret the teleconverter purchase.
I am not considering the 100-600 due to weight. I have loved the lightness of the 500 5.6 pf.
Another part of me says maybe just keep the 500 and be happy with what I have.
I'd love to get the 600 :/
800 seems a bit cumbersome and once again, that little bit heavier might make me need something to help steady it. I love being able to easily hand hold. Plus the 600 travels easier than the 800.

I rented the 800 and thought it was too big. But later I got one anyway and it proved to be the best decision I made.

The reality for me is when I looked hard at what I needed for photographing birds I needed to work at 800mm a lot. The 800 is the least expensive and best way to get there. You are shooting at f6.3 which is only one third of a stop from the most expensive options at that length.

If you get the 600mm f6.3 you will end up having to shoot at f9.

There are options for carrying the 800:

1. You can use a monopod. Makes handling the lens much easier.
2. Get a good carry strap (Blackrapid, Holdfast). You can carry the lens/camera dangling by your side, pick it up only to shoot it, then let it back down. You can work handheld for hours that way.f
3. Use a tripod and gimbal when you can shoot near a vehicle. WHen it is on the tripod/gimbal it is super easy to track and pan. Plus the tripod will improve image quality.
4. Get an inexpensive wheeled cart. In flat terrain wheel it to where you are going. I have seen people do this when shooting in zoos.

The 800mm pf is often available used for good prices because those with money to burn upgrade to the 600 tc.

You don’t need a tc with the 800. I never bother using a tc with this lens because it crops very well when shooting at 800. So when comparing price look at how much it costs for the 600 pf plus 1.4 tc versus what you can get a used 800 for. They are actually closer in price than you would think.

 

[EricBowles]

I'm debating along similar lines. I have the 500 5.6 pf. that I use with my Z9. I like it a lot. I would like more reach. Is it feasible or practical to get the 600 6.3 ? The 6.3 is bothersome, I'd rather something that works better in low light but I know 5.6 to 6.3 isn't that bad, better than the teleconverter. I DID get a teleconverter but I hate putting the thing on and off. I do regret the teleconverter purchase.
I am not considering the 100-600 due to weight. I have loved the lightness of the 500 5.6 pf.
Another part of me says maybe just keep the 500 and be happy with what I have.
I'd love to get the 600 :/
800 seems a bit cumbersome and once again, that little bit heavier might make me need something to help steady it. I love being able to easily hand hold. Plus the 600 travels easier than the 800.

Try a full day in the field using the 500mm PF and the 1.4 TC. It will help give you an idea of what more focal length is really like. If you find you still lack reach, the 800mm PF is your answer in spite of the weight. If you think the 500mm PF + TC is appropriate all day, you probably need something longer and the 600mm PF is a good compromise. You don't want a solution that requires a TC all of the time, you don't want to always use the long end of your zoom lens, and you don't want to always need a significant crop. Buy the lens you need for what you are going to shoot. Once you figure out the focal length, you can decide how to get there and whether lighter options are available.

For what it's worth, you might need different field strategies or better field craft if 500mm or 600mm are not long enough but you don't want the 800mm PF. That's also a choice.

 

[Brian L]

I have both the 500pf and 600pf and shoot the Z8 - and, nostalgically, at times my D850.

My vote is the 600pf, the difference in reach - 20% more - is noticeable. With the 45MP sensor on the Z8, I often extend the effective range of the 600 by either shooting in DX mode or cropping later. 20MP still yields great quality - I also shoot the M43 OM1 - except for pixel snobs.

Even if you have to trade in your 500 to swing it, you won’t regret the choice.

 

[bleirer]

While I get the 20% more reach thing, I think I'd be more concerned with lens quality over the improvement in field of view. If you shoot at 600 at 50 feet, the 500 would get the same image at about 42 feet. Not nothing, but the 600 also has to be at least as good of a lens to be a candidate. Sounds like a better lens combined with more reach as described is an easy decision.

 

[NWGuy]

Some good and thoughtful comments here, lots of food for thought and/or to confound the issue. Trying to come up with the ideal kit for one's particular shooting preferences is never easy, more difficult with wider interests in targets. I shoot the Z8 mainly wildlife, have the Z100-400 (if my wife ever lets me use it), and the 180-600 plus some shorter lenses. I tend to shoot mostly at the far end of the 180-600 and thus have been considering the prime 600 or even 800 (pf's). But really like the option of the zoom either when target is close or wanting more of an environmental shot. Not real excited about constantly changing lenses or carrying two bodies both with heavy lenses. I also shoot for me, not selling my photos, so the requirement of near perfect IQ is not such a heavy burden. Too bad Nikon did not make the decision to make the 180-600 more in line with a S lens (granted, would've cost more, so I understand their marketing plan).

 

[wotan1]

I think it is wise to have a long range plan.

I know about the 500/600 issues because I saw my photo buddy go through it.

The full history here is that I was initially shooting with teh 400 f4.5 while he was shooting 500 pf. I saw him having advantages over what I had.

We both at that point wanted to add the 180-600 because of the price and early ratings. When neither of us had any hope of actually getting one of these lenses for the foreseeable future, I jumped on the 600 pf when it first came out, and my photo buddy followed through shortly after.

Both of us noted improvement with the 600 Pf. I had a lot more reach and used it with the 1.4x tc a lot. Reports from him were that the 600 was marginally sharper but also of course had more reach.

But both of us shot the same locations which means we did a lot in the 800mm range. Both of us had problems from time to time with atmospheric issues when shooting at 600mm and longer.

Later I got the 800mm PF and have been thoroughly impressed by its performance. I ended up stopping using the 600mm pf when the 800 was possible. My friend still has the 600 and we compare shots from time to time. I think he has seen what the 800 can do but he is not ready to spend the money on another lens.

Once I got the 800 running I pretty much stopped using the 600. I eventually decided to sell it.

My shorter lenses are the 70-200mm f2.8 and the 400mm f4.5. Between them and the 800 I feel very comfortable in what I can accomplished in the wildlife world.

I would love one of the super primes and am leaning towards the 400mm f2.8 tc vr s. I will go there eventually most likely but that is not in the cards this year or probably next.

The 600mm pf has the advantage over the 500 of going out to 840 with the 1.4 tc. At that point it can still use crop/dx but it is stuck with F9 maximum aperture.

The 800mm is simply sharper than the 600mm pf with tc in this range and it also does better with crop/dx. I also think they did a better job with bokeh on this lens so backgrounds are more interesting. It certainly helps that the 800 is at f6.3 which is within one third of an F stop of the best lenses on the market at 800.

That is my direct experience with the lenses that I and my photo buddy who is a great photographer have done.

 

[Ken Miracle]

I think it is wise to have a long range plan.

I know about the 500/600 issues because I saw my photo buddy go through it.

The full history here is that I was initially shooting with teh 400 f4.5 while he was shooting 500 pf. I saw him having advantages over what I had.

We both at that point wanted to add the 180-600 because of the price and early ratings. When neither of us had any hope of actually getting one of these lenses for the foreseeable future, I jumped on the 600 pf when it first came out, and my photo buddy followed through shortly after.

Both of us noted improvement with the 600 Pf. I had a lot more reach and used it with the 1.4x tc a lot. Reports from him were that the 600 was marginally sharper but also of course had more reach.

But both of us shot the same locations which means we did a lot in the 800mm range. Both of us had problems from time to time with atmospheric issues when shooting at 600mm and longer.

Later I got the 800mm PF and have been thoroughly impressed by its performance. I ended up stopping using the 600mm pf when the 800 was possible. My friend still has the 600 and we compare shots from time to time. I think he has seen what the 800 can do but he is not ready to spend the money on another lens.

Once I got the 800 running I pretty much stopped using the 600. I eventually decided to sell it.

My shorter lenses are the 70-200mm f2.8 and the 400mm f4.5. Between them and the 800 I feel very comfortable in what I can accomplished in the wildlife world.

I would love one of the super primes and am leaning towards the 400mm f2.8 tc vr s. I will go there eventually most likely but that is not in the cards this year or probably next.

The 600mm pf has the advantage over the 500 of going out to 840 with the 1.4 tc. At that point it can still use crop/dx but it is stuck with F9 maximum aperture.

The 800mm is simply sharper than the 600mm pf with tc in this range and it also does better with crop/dx. I also think they did a better job with bokeh on this lens so backgrounds are more interesting. It certainly helps that the 800 is at f6.3 which is within one third of an F stop of the best lenses on the market at 800.

That is my direct experience with the lenses that I and my photo buddy who is a great photographer have done.

About 600-800 "bokeh" or what ever we want to call it keep in mind that if you use the 600 and 800 on the same subject at the same distance and the same f/stop the background will be more in focus with the 600 (less compression). Depending on the distance to the subject and how far the subject is from the background the bokeh impression will change.

I have not shot the 600 f/6.3 enough yet to notice any apples to apples difference yet and have used the 600 more on the Z6III than the Z9 so not a lot of apples to apples comparison yet.

 

[wotan1]

About 600-800 "bokeh" or what ever we want to call it keep in mind that if you use the 600 and 800 on the same subject at the same distance and the same f/stop the background will be more in focus with the 600 (less compression). Depending on the distance to the subject and how far the subject is from the background the bokeh impression will change.

I have not shot the 600 f/6.3 enough yet to notice any apples to apples difference yet and have used the 600 more on the Z6III than the Z9 so not a lot of apples to apples comparison yet.

I don’t understand this comment.

The whole point with a ”faster” lens is that you can shoot at a wider aperture. A wider aperture involves less depth of field which allows you to defocus the background so the main subject stands out better. A second advantage is that the “faster” lens can shoot at a lower ISO as well as in lower light situations. Yet a third advantage is that some of the autofocus mechanisms do better with wider apertures so the “faster” lens will autofocus better.

Photographers pay a lot of money to get those wide apertures. They spend the money because the wide apertures allow you to do things that can’t be done with “slower” lenses.

If you are shooting with the 600mm pf and you want an 800mm equivalent shot you must choose either to add a 1.4x tc or you can crop or go to dx mode. If you shoot wide open and crop or dx you will have the same maximum aperture as the 800mm BUT you will only be using a portion of the frame. If you shoot with the 800 at 800 you will be using the full frame.

If you can fill the frame with the 600 crop to 800 you should for practical purposes have the same practical quality image as the 800. This assumes you are working with a 47mp camera. However, if further cropping at 800mm is needed the 800mm will have a significant advantages because it has more pixels to work with.

If on the other hand you choose to use a teleconverter on the 600 to get to 800 you will be working with more or less the same size image on the sensor (the 600 is actually at 840 so slightly more reach). However when using the 1.4 tc you are already down to F9 on the 600 compared to the 800 at f6.3.

When shooting birds I am pretty much always shooting wide open. I normally have no reason to want to shoot f9 when birding, I am going to be at f6.3. I am simply going to have less depth of field and be able to defocus backgrounds much better with the native 800 than the 600 with tc. I can also shoot in lower light situations and with better ISO.

The 800 in my experience has significant advantages over the 600 with a tc. It has better IQ which means in a large megapixel camera you have considerably more room to crop or go dx. I shoot 20fps bursts and find a lot of keepers in post I did not know were there. It also shoots wider open meaning better separation of the subject from the distracting background. Plus it works really welll with autofocus once you get the subject in the frame.

Like I said I shot both of these lenses side by side. I stopped using the 600 at 800mm because the native 800mm pf simply gave me more to work with. This is based on personal experience.

 

[Ken Miracle]

I don’t understand this comment.

The whole point with a ”faster” lens is that you can shoot at a wider aperture. A wider aperture involves less depth of field which allows you to defocus the background so the main subject stands out better. A second advantage is that the “faster” lens can shoot at a lower ISO as well as in lower light situations. Yet a third advantage is that some of the autofocus mechanisms do better with wider apertures so the “faster” lens will autofocus better.

Photographers pay a lot of money to get those wide apertures. They spend the money because the wide apertures allow you to do things that can’t be done with “slower” lenses.

If you are shooting with the 600mm pf and you want an 800mm equivalent shot you must choose either to add a 1.4x tc or you can crop or go to dx mode. If you shoot wide open and crop or dx you will have the same maximum aperture as the 800mm BUT you will only be using a portion of the frame. If you shoot with the 800 at 800 you will be using the full frame.

If you can fill the frame with the 600 crop to 800 you should for practical purposes have the same practical quality image as the 800. This assumes you are working with a 47mp camera. However, if further cropping at 800mm is needed the 800mm will have a significant advantages because it has more pixels to work with.

If on the other hand you choose to use a teleconverter on the 600 to get to 800 you will be working with more or less the same size image on the sensor (the 600 is actually at 840 so slightly more reach). However when using the 1.4 tc you are already down to F9 on the 600 compared to the 800 at f6.3.

When shooting birds I am pretty much always shooting wide open. I normally have no reason to want to shoot f9 when birding, I am going to be at f6.3. I am simply going to have less depth of field and be able to defocus backgrounds much better with the native 800 than the 600 with tc. I can also shoot in lower light situations and with better ISO.

The 800 in my experience has significant advantages over the 600 with a tc. It has better IQ which means in a large megapixel camera you have considerably more room to crop or go dx. I shoot 20fps bursts and find a lot of keepers in post I did not know were there. It also shoots wider open meaning better separation of the subject from the distracting background. Plus it works really welll with autofocus once you get the subject in the frame.

Like I said I shot both of these lenses side by side. I stopped using the 600 at 800mm because the native 800mm pf simply gave me more to work with. This is based on personal experience.

The point I was making was just about "bokeh" and compression the longer the focal length used on the same subject with the same settings at the same distance with the same background the less in focus the background is ... what some call "bokeh"

 

[NorthernFocus]

I don’t understand this comment.
...

The point I was making was just about "bokeh" and compression the longer the focal length used on the same subject with the same settings at the same distance with the same background the less in focus the background is ... what some call "bokeh"

I think what Ken is saying is that if you stand in the same spot and shoot the same subject with 800PF and 600PF the bokeh will be better with the 800. Stands to reason as under those conditions the DOF will be much deeper with the 600. So even if you crop to the same effective FOV the bokeh won't be as smooth with the 600.

 

[wotan1]

Got it thank you.

 

[bleirer]

This is neither here nor there, but I thought it was interesting how we can confuse the bokeh from depth of field with the fact that the background blur can be relatively bigger if we are farther away from our subject.

As a rule of thumb it goes with multiples of the camera to foreground subject distance. If we are 20 feet from the subject then at 40 feet from us something the same size will appear to be half as big, at 60 feet from us it will be 1/3 the size, at 80 feet 1/4, and so on. If we are 50 feet from the subject then at 100 feet something of the same size will appear to be half as big, at 150 feet 1/3, and at 200 feet 1/4. In other words the farther away we start the bigger the blur appears and maybe that makes it nicer/creamier.

 

[TurtleCat]

This is neither here nor there, but I thought it was interesting how we can confuse the bokeh from depth of field with the fact that the background blur can be relatively bigger if we are farther away from our subject.

As a rule of thumb it goes with multiples of the camera to foreground subject distance. If we are 20 feet from the subject then at 40 feet from us something the same size will appear to be half as big, at 60 feet from us it will be 1/3 the size, at 80 feet 1/4, and so on. If we are 50 feet from the subject then at 100 feet something of the same size will appear to be half as big, at 150 feet 1/3, and at 200 feet 1/4. In other words the farther away we start the bigger the blur appears and maybe that makes it nicer/creamier.

From my POV the further the background is from the subject is of more import to me. So you can make slow lenses look good but the background has to be a lot further away. So with regard to the 500 and 600mm, you would get the same in frame if you’re 20% closer (generally) and with the closer perspective your DOF will be narrower anyway.

 

[EricBowles]

From my POV the further the background is from the subject is of more import to me. So you can make slow lenses look good but the background has to be a lot further away. So with regard to the 500 and 600mm, you would get the same in frame if you’re 20% closer (generally) and with the closer perspective your DOF will be narrower anyway.

Another benefit is having a narrow field of view allows you to pick the background you want. I had a western meadowlark on a nice perch and had a choice of sky, green grass, or a tan meadow for my background by moving just a few inches. Of course, with a longer lens the background can be too out of focus so you need to stop down to have the right degree of out of focus background. Sometimes you want to keep the scene or environment.

 

[Ken Miracle]

This is neither here nor there, but I thought it was interesting how we can confuse the bokeh from depth of field with the fact that the background blur can be relatively bigger if we are farther away from our subject.

As a rule of thumb it goes with multiples of the camera to foreground subject distance. If we are 20 feet from the subject then at 40 feet from us something the same size will appear to be half as big, at 60 feet from us it will be 1/3 the size, at 80 feet 1/4, and so on. If we are 50 feet from the subject then at 100 feet something of the same size will appear to be half as big, at 150 feet 1/3, and at 200 feet 1/4. In other words the farther away we start the bigger the blur appears and maybe that makes it nicer/creamier.

However that is only part of the equation. Another factor is how far the subject is from the background (and foreground when dealing with birds in a bush or tree) and of course eventually the aperture comes into play. The longer the focal length the further you can be from the subject and the background. The further away the subject is from the background the less defined it is.

Long focal length lenses by their nature have a compression factor. For instance if you are photographing a sea lion with rolling waves (not breakers) behind it the waves will appear bigger and taller than they are, as you said the background is bigger. Also why some landscapes may be shot with longer focal length to compress layers but bring them into play.

In fact I have used 600 and 800mm to do that although 200 to 400mm is more common, but I am a birder and 800 or 600 is frequently in hand when an unusual landscape opportunity popped up (think layers of early light mountains when I am standing on a mountain looking accross at the scene).

And of course there is that infinity distance issue that brings everything into focus and of course that distance is much longer with and 800 mm than a 24 mm

And yes the construction of the optics themselves come into play ... the 135mm Plena has a whole different job to do than an Z800 mm f/6.3 pf

 

[Ken Miracle]

Another benefit is having a narrow field of view allows you to pick the background you want. I had a western meadowlark on a nice perch and had a choice of sky, green grass, or a tan meadow for my background by moving just a few inches. Of course, with a longer lens the background can be too out of focus so you need to stop down to have the right degree of out of focus background. Sometimes you want to keep the scene or environment.

Yup .. more moving parts that you can "shake a stick at" And some times I get the luxury of a few seconds to shoot for prettier after the ID shot is in the bag. I was trying to photograph a Black-capped Chickadee today when a Yellow Warbler flew in front of it and an unkown brown bird popped onto a branch in my field of view. I quickly go the ID on the unknown (turned out to be a Song Sparrow) then quickly panned over and got the ID shots on the frenetic Yellow Warbler chasing bugs in a bush and by then the Chickadee had vanished

 

[bleirer]

Part of what I was trying to get across is long lenses don't have a compression factor. It's the distance camera to subject and camera to background that creates the feeling of compression. Of course we often naturally choose a long focal length when farther away, so they go hand in hand in that sense, but the compression would happen with any lens at the same distance.

If the subject is 20 feet from the camera and a same size background object is 40 feet from the camera, the background object will be 10/20 or 50% the size of the foreground one. If a subject is 50 feet from the camera and a same sized background object was 20 feet behind at 70 feet from the camera then the background object would be 50/70 or 71% of the foreground, no matter which lens.

 

[Ken Miracle]

Part of what I was trying to get across is long lenses don't have a compression factor. It's the distance camera to subject and camera to background that creates the feeling of compression. Of course we often naturally choose a long focal length when farther away, so they go hand in hand in that sense, but the compression would happen with any lens at the same distance.

If the subject is 20 feet from the camera and a same size background object is 40 feet from the camera, the background object will be 10/20 or 50% the size of the foreground one. If a subject is 50 feet from the camera and a same sized background object was 20 feet behind at 70 feet from the camera then the background object would be 50/70 or 71% of the foreground, no matter which lens.

The other issue in your example would be a shorter focal length already at infinity with subject at 50 feet and background 20 feet behind that the depth of field for a Z 50 mm f/1.8 or Z14-30 f/4 is signficantly different than a Z800 f/6.3 pf or even a Z600 f/6.3 .... those are radical differences of course. There is also far less of a "magnification" factor so the perception of size difference between the subject and background is quite different.

What I need for birds and great bokeh is an 800mm Plena ... That would be one heavy in the hand and pocket book lens

 

[wotan1]

800mm Plena is a great idea.