Antal I Kozma wrote:Hi to all,Interesting find. I suppose we still have to take it as "anything can happen". Meaning either it is true, false, correct or incorrect.Here is my opinion about a 500mm f5.6 PF:if it is true then it is a mistake.What is my logic behind my opinion? Well, there is a fairly decent 200-500mm f5.6 Nikkor, it is light as far as super zooms go and optically excellent with exceptional VR.Then, above mentioned zoom is reasonably affordable. So why would I, or anyone else, spend thousands more to have the same focal length and f stop? Yes, it likely will focus faster being a prime lens but that would be the only major improvement. Would it worth three thousand extra? Not with any reasonable logic I would say.We know how expensive the Nikon exotic telephoto lenses are. So most who cannot afford those look for alternative solutions. Therefore they buy a Nikkor 200-500mm , a Tamron 150-600mm or one of the Sigma offerings. How would a 500mm f 5.6 prime lens would fit into this picture?I could see a 600mm f 5.6 lens as a viable offering but not a 500mm one. Why? 600mm is what many who are into wildlife or birding really wish to have. A 600mm f5.6 PF with much lighter weight than its f4 counterpart for $4,500.00-5,000.00 would be much more affordable and handy. Due to being a prime lens it would focus much faster than the above mentioned zooms. It would only sacrifice one f stop over its f4 cousin but given its easier handling this lens would be excellent for birding and wildlife.Put a 1.4x converter on the 600 mm lens and you have a 840mm f8 lens that would still be reasonably usable with a D500 or D5 in the ISO 400-1600 range. On the other hand the shorter 500mm would go up to 700mm f8, only 100mm over the Tamron and Sigma zooms while sacrificing 2/3 of a stop to do that. Not enough of an advantage in my practice.I like the 500mm f4E FL with a 1.4x converter. 700mm at f5.6 is very usable as far as I can attest to it. Would I use a 500mm f5.6 with a converter for about three thousand dollars more than a Tamron 150-600 G2 to gain 100mm extra while losing 2.3 of a stop when compared to the Tamron? Absolutely not.Anyway, this is my take on the possible 500mm f5.6 PF Nikkor. I wish it would show up as a 600mm f5.6. That would tickle my fancy.Best to all, AIKThe 500mm f/5.6 PF is definitely a mistake. What do you think Nikon is thinking, or are they even thinking?I mean, how on earth could a prime lens outdo a lackadaisical, glacially-slow-at-focusing budget zoom (200-500 f/5.6)? That would be truly unprecedented, right?

Antal I Kozma wrote:Hi to all,Interesting find. I suppose we still have to take it as "anything can happen". Meaning either it is true, false, correct or incorrect.Not really - Nikon have actually made a formal announcement about this lens.  The rumours are just about the timing of its release, its size, weight and price.Here is my opinion about a 500mm f5.6 PF:if it is true then it is a mistake.What is my logic behind my opinion? Well, there is a fairly decent 200-500mm f5.6 Nikkor, it is light as far as super zooms go and optically excellent with exceptional VR.Then, above mentioned zoom is reasonably affordable. So why would I, or anyone else, spend thousands more to have the same focal length and f stop?Maybe you wouldn't, but others might consider it worth spending more for even better image quality, faster AF, less bulk, less weight and (possibly) better results with a TC.Yes, it likely will focus faster being a prime lens but that would be the only major improvement. Would it worth three thousand extra? Not with any reasonable logic I would say.We know how expensive the Nikon exotic telephoto lenses are. So most who cannot afford those look for alternative solutions. Therefore they buy a Nikkor 200-500mm , a Tamron 150-600mm or one of the Sigma offerings. How would a 500mm f 5.6 prime lens would fit into this picture?I could see a 600mm f 5.6 lens as a viable offering but not a 500mm one. Why? 600mm is what many who are into wildlife or birding really wish to have. A 600mm f5.6 PF with much lighter weight than its f4 counterpart for $4,500.00-5,000.00 would be much more affordable and handy. Due to being a prime lens it would focus much faster than the above mentioned zooms. It would only sacrifice one f stop over its f4 cousin but given its easier handling this lens would be excellent for birding and wildlife.You believe that a 500mm f/5.6E PF would have little benefit compared with a 200-500mm f/5.6E, but that a 600mm f/5.6E PF would have significant advantages over (say) a Sigma 150-600mm f/5-6.3 Sport zoom? I don't follow your logic.Put a 1.4x converter on the 600 mm lens and you have a 840mm f8 lens that would still be reasonably usable with a D500 or D5 in the ISO 400-1600 range. On the other hand the shorter 500mm would go up to 700mm f8, only 100mm over the Tamron and Sigma zooms while sacrificing 2/3 of a stop to do that. Not enough of an advantage in my practice.I like the 500mm f4E FL with a 1.4x converter. 700mm at f5.6 is very usable as far as I can attest to it. Would I use a 500mm f5.6 with a converter for about three thousand dollars more than a Tamron 150-600 G2 to gain 100mm extra while losing 2.3 of a stop when compared to the Tamron? Absolutely not.Anyway, this is my take on the possible 500mm f5.6 PF Nikkor. I wish it would show up as a 600mm f5.6. That would tickle my fancy.

Cloven Hoof wrote:Antal I Kozma wrote:Hi to all,Interesting find. I suppose we still have to take it as "anything can happen". Meaning either it is true, false, correct or incorrect.Here is my opinion about a 500mm f5.6 PF:if it is true then it is a mistake.What is my logic behind my opinion? Well, there is a fairly decent 200-500mm f5.6 Nikkor, it is light as far as super zooms go and optically excellent with exceptional VR.Then, above mentioned zoom is reasonably affordable. So why would I, or anyone else, spend thousands more to have the same focal length and f stop? Yes, it likely will focus faster being a prime lens but that would be the only major improvement. Would it worth three thousand extra? Not with any reasonable logic I would say.We know how expensive the Nikon exotic telephoto lenses are. So most who cannot afford those look for alternative solutions. Therefore they buy a Nikkor 200-500mm , a Tamron 150-600mm or one of the Sigma offerings. How would a 500mm f 5.6 prime lens would fit into this picture?I could see a 600mm f 5.6 lens as a viable offering but not a 500mm one. Why? 600mm is what many who are into wildlife or birding really wish to have. A 600mm f5.6 PF with much lighter weight than its f4 counterpart for $4,500.00-5,000.00 would be much more affordable and handy. Due to being a prime lens it would focus much faster than the above mentioned zooms. It would only sacrifice one f stop over its f4 cousin but given its easier handling this lens would be excellent for birding and wildlife.Put a 1.4x converter on the 600 mm lens and you have a 840mm f8 lens that would still be reasonably usable with a D500 or D5 in the ISO 400-1600 range. On the other hand the shorter 500mm would go up to 700mm f8, only 100mm over the Tamron and Sigma zooms while sacrificing 2/3 of a stop to do that. Not enough of an advantage in my practice.I like the 500mm f4E FL with a 1.4x converter. 700mm at f5.6 is very usable as far as I can attest to it. Would I use a 500mm f5.6 with a converter for about three thousand dollars more than a Tamron 150-600 G2 to gain 100mm extra while losing 2.3 of a stop when compared to the Tamron? Absolutely not.Anyway, this is my take on the possible 500mm f5.6 PF Nikkor. I wish it would show up as a 600mm f5.6. That would tickle my fancy.Best to all, AIKThe 500mm f/5.6 PF is definitely a mistake. What do you think Nikon is thinking, or are they even thinking?I mean, how on earth could a prime lens outdo a lackadaisical, glacially-slow-at-focusing budget zoom (200-500 f/5.6)? That would be truly unprecedented, right?Such low sarcasm is unbecoming of you my dear. I thought you were supposed to be our most witty contributor.The question is going to be whether Nikon can sell enough of these extravagantly priced slow lenses not to make themselves look silly. Or whether it's going to end up like the Canon 70-300 DO which you find settles to 1/3 of its new price on the used market.When I think of the $100 400mm f5.6 I had lying around, and the idea of a 500mm f5.6 with VR to justify another $4200, I wonder if Nikon are laughing behind the parapet like the French knights in Monty Python.

briantilley wrote:You believe that a 500mm f/5.6E PF would have little benefit compared with a 200-500mm f/5.6E, but that a 600mm f/5.6E PF would have significant advantages over (say) a Sigma 150-600mm f/5-6.3 Sport zoom? I don't follow your logic.Hi,As I said these are my thoughts, I understand that others see things differently and use a different set of their own logic.My logic for preferring a 600mm f5.6 over a zoom, especially the nose heavy Sigma Sport, come from field experience with the 500m F4E Fl, the 200-500mm Nikkor and the 150-600mm Tamron G2 in shooting environments I usually find myself.A short and light 600mm f5.6 might give hell of an advantage over the front heavy Sigma Sport. I handled this lens on a couple of outings and gave up on it for being so front heavy. A 600mm f5.6 prime lens with snappier focusing and much better weight distribution should result in a much higher keeper rate. Especially when one photographs swiftly moving small songbirds in heavy thicket of shrubs or marsh vegetation.Going back to the 500mm prime and zoom question. First of all I find 500mm just a tad short in small bird photography. Although many are absolutely happy with the Nikkor 200-500mm zoom I gave mine to my grandson. I opted for the 150-600mm Tamron G2. The Nikkor is optically excellent but was slow in the AF department for my use. The extra 100mm of the Tamron G2, giving up only 1/3 f stop works for me for small birds much better. It also focuses faster than the Nikkor, optically comparable, its VC is as good as Nikon's VR.Now, I do like the Tamron 150-600mm G2 for what it is. However, if a 600mm f5.6 smallish prime would come along I would adopt that for further increased AF speed, 1/3 stop more light gathering and less busy background rendering. On the other hand I would not step backwards to 500mm and lose 100mm reach. I also would not be happier with attaching a 1.4x converter to it and go down to f8. That would slow the AF speed and would make the background busier in above mentioned shooting environments.When I use my 500mm F4E FL prime for small songbirds I use it exclusively with the 1.4x converter. 700mm at f5.6 is great. I use this combo wide open or 1/3 stop closed down. However, I would consider using an even lighter 600mm f5.6 for handling ease and weight savings. Yes, I would step back 100mm in this case but I would be still in the 600mm range that suits me when I use 600mm on a D500.Let's see the 500mm f5.6 vs 200-500mm f5.6 pros and cons. The prime would definitely focus faster but it would cost about three thousand more than the zoom. This is a question of budget which I would not go for. Then, the prime is still the same focal length and aperture as the zoom. Nothing much gained there but some AF sped. However, the zoom gives framing flexibility for those who need it. I only would use a 200-500mm zoom for general wildlife and not for birding. Then the zoom feature would worth more for my use than the AF speed of the prime. And again, the cost savings are significant.So in closing, I think that Nikon would have done a much better home run with a 600mm f5.6. That would take the bird and wildlife photographer closer to the coveted 600mm f4 E FL with a reasonably affordable price as of primes go.Well, these are my points of logic and they apply for my shooting based on the experience I accumulated in the environment I photograph.You see, it is tempting to say that "I have a 500mm f5.6" Nikkor prime. However, for how much more than the 200-500mm zoom and for how much practical gain? In this case I rather would stay with the 150-600mm Tamron G2. It is optically excellent, reasonably fast in the AF department, good VC and 100mm focal length gain. All this for 1/3 stop light loss but with the convenience of zoom capability when needed.Best, AIK

michaeladawson wrote:DiffractionLtd wrote:Sorry, I was tired and in a hurry, but I didn't think it would be $10k because lenses slower by a stop are usually a couple orders of magnitude cheaper.A couple of orders of magnitude?? An order of magnitude is generally considered to be a 10X difference. I don't thing the 500mm f/5.6 will be selling for $100. Or even a $1000.Yeah sure.  Go all technical about it.

nuke12 wrote:DiffractionLtd wrote:Lance B wrote:DiffractionLtd wrote:The 500mm f/4.0 costs a lot more though. But look how short this thing is. Must be some heavy negative lenses in it to make it 500mm.https://petapixel.com/2018/07/14/nikon-500mm-f-5-6-spotted-its-tiny/It's rumored to be $4,300, not $10,000.It does look small for a 500mm f5.6.Conflicting reports of price. $4,300 though sounds more realistic.Where did you get your price from?https://nikonrumors.com/2018/07/06/nikon-af-s-nikkor-500mm-f-5-6e-pf-ed-vr-lens-additional-information-price-and-length.aspx/

Antal I Kozma wrote:briantilley wrote:You believe that a 500mm f/5.6E PF would have little benefit compared with a 200-500mm f/5.6E, but that a 600mm f/5.6E PF would have significant advantages over (say) a Sigma 150-600mm f/5-6.3 Sport zoom? I don't follow your logic.Hi,As I said these are my thoughts, I understand that others see things differently and use a different set of their own logic.Fair enough - though in your earlier post you did seem to suggest that you expect most others will share your view, when you said (my italics):"So why would I,or anyone else, spend thousands more to have the same focal length and f stop?"My logic for preferring a 600mm f5.6 over a zoom, especially the nose heavy Sigma Sport, come from field experience with the 500m F4E Fl, the 200-500mm Nikkor and the 150-600mm Tamron G2 in shooting environments I usually find myself.A short and light 600mm f5.6 might give hell of an advantage over the front heavy Sigma Sport. I handled this lens on a couple of outings and gave up on it for being so front heavy. A 600mm f5.6 prime lens with snappier focusing and much better weight distribution should result in a much higher keeper rate. Especially when one photographs swiftly moving small songbirds in heavy thicket of shrubs or marsh vegetation.My point is that the same advantages apply to a 500mm f/5.6E PF over the 200-500mm f/5.6E.  These things will be of benefit to those people who prefer the 500mm focal length over 600mm.  Such people must exist - after all the 500mm f/4E outsells the 600mm f/4E by more than 2:1

What a great lens. Well done Nikon. I really feel that Canon, with its fantastic great whites, is still lacking in the value telephoto department.

T O Shooter wrote:michaeladawson wrote:DiffractionLtd wrote:Sorry, I was tired and in a hurry, but I didn't think it would be $10k because lenses slower by a stop are usually a couple orders of magnitude cheaper.A couple of orders of magnitude?? An order of magnitude is generally considered to be a 10X difference. I don't thing the 500mm f/5.6 will be selling for $100. Or even a $1000.Yeah sure. Go all technical about it.Old "girlwatcher" 500mm f/8.0 lenses sell for about $50.00 so all they need to do is drop it one more stop!

Antal I Kozma wrote:Now, I do like the Tamron 150-600mm G2 for what it is. However, if a 600mm f5.6 smallish prime would come along I would adopt that for further increased AF speed, 1/3 stop more light gathering and less busy background rendering. On the other hand I would not step backwards to 500mm and lose 100mm reach. I also would not be happier with attaching a 1.4x converter to it and go down to f8. That would slow the AF speed andwould make the background busier in above mentioned shooting environments.Sounds like you are suggesting that you get more DOF with the TC attached because you are now at f/8?  Hence a busier background.I think that is quite correct.  All a TC does is enlarge the image coming from the main lens.  The f/8 is from loss of light from the enlargement process.

michaeladawson wrote:Antal I Kozma wrote:Now, I do like the Tamron 150-600mm G2 for what it is. However, if a 600mm f5.6 smallish prime would come along I would adopt that for further increased AF speed, 1/3 stop more light gathering and less busy background rendering. On the other hand I would not step backwards to 500mm and lose 100mm reach. I also would not be happier with attaching a 1.4x converter to it and go down to f8. That would slow the AF speed andwould make the background busier in above mentioned shooting environments.Sounds like you are suggesting that you get more DOF with the TC attached because you are now at f/8? Hence a busier background.I think that is quite correct. All a TC does is enlarge the image coming from the main lens. The f/8 is from loss of light from the enlargement process.Mike, you might be right on this. I have not thought about this as you pointed it out.I simply went by my experience when shooting with the 500mm f4E FL with and without the 1.4x TC III. I have always felt that the background was busier when the TC was used, which is most often on the lens.It can simply happen that it was the actual scenery that made me feel that the background business increased.Thanks for pointing this out. Anyhow, I would be much much happier if Nikon would have developed a 600mm f5.6 lens. That definitely would become my most used birding and wildlife lens. Light and short and 600mm with a still good wide aperture, oh boy, it is a dream of mine.Someone else pointed it out that the 500mm f4 is the most popular in the exotic line up of Nikon's telephoto lenses. I definitely agree, I too opted for the 500mm lens. However, my reasoning was not that it is 500mm that would be my preferred focal length. I chose it because that lens was the one I could still use with a 1.4x converter hand held. 700mm f5.6 is not bad for reach and on the edge of my physical capability to carry it for hours in hand. I would not be able to do that with a 600mm f4. However, I could carry a light 600mm f5.6 for days in a row.I would sacrifice the reach of the 500mm + 1.4x for the weight and mobility advantages of a 600mm f5.6. However, I would not go back to 500mm only. As I mentioned earlier I rather carry my Tamron G2 and shoot at 600mm f6.3 when I need a lighter outfit for day long trekking.Now, I have no doubt that many will adopt this lens for their use. It is an "exotic lens", comes with bragging rights too. Then of course people who do not need the reach of a 600mm lens will take good use of this lens. When I said that I do not know why others would opt for this lens I was not clear enough. I meant those who do need more reach for something like tiny kinglets and warblers. For those the 500mm f5.6 might be less useful than a Tamron 150-600mm f6.3 G2.Best, AIK

Bill Ferris wrote:nuke12 wrote:DiffractionLtd wrote:Lance B wrote:DiffractionLtd wrote:The 500mm f/4.0 costs a lot more though. But look how short this thing is. Must be some heavy negative lenses in it to make it 500mm.https://petapixel.com/2018/07/14/nikon-500mm-f-5-6-spotted-its-tiny/It's rumored to be $4,300, not $10,000.It does look small for a 500mm f5.6.Conflicting reports of price. $4,300 though sounds more realistic.Where did you get your price from?https://nikonrumors.com/2018/07/06/nikon-af-s-nikkor-500mm-f-5-6e-pf-ed-vr-lens-additional-information-price-and-length.aspx/I was asking the OP Bill because his price seemed so far out of wack.

michaeladawson wrote:Antal I Kozma wrote:Now, I do like the Tamron 150-600mm G2 for what it is. However, if a 600mm f5.6 smallish prime would come along I would adopt that for further increased AF speed, 1/3 stop more light gathering and less busy background rendering. On the other hand I would not step backwards to 500mm and lose 100mm reach. I also would not be happier with attaching a 1.4x converter to it and go down to f8. That would slow the AF speed andwould make the background busier in above mentioned shooting environments.Sounds like you are suggesting that you get more DOF with the TC attached because you are now at f/8? Hence a busier background.I think that is quite correct. All a TC does is enlarge the image coming from the main lens. The f/8 is from loss of light from the enlargement process.One way of describing how a TC magnifies, is to say mounting a TC to a lens creates a "new" lens with a longer focal length. The longer focal length produces a narrower angle of view; more magnification. That new, longer focal length paired with the same physical aperture translates to an increased focal ratio (f-stop) from f/5.6 to f/8 and less light captured during a same-length exposure made at f/5.6. It also produces an increased depth of field compared, again to an exposure made from the same location, with the same physical aperture but a shorter focal length.

Bill Ferris wrote:michaeladawson wrote:Antal I Kozma wrote:Now, I do like the Tamron 150-600mm G2 for what it is. However, if a 600mm f5.6 smallish prime would come along I would adopt that for further increased AF speed, 1/3 stop more light gathering and less busy background rendering. On the other hand I would not step backwards to 500mm and lose 100mm reach. I also would not be happier with attaching a 1.4x converter to it and go down to f8. That would slow the AF speed andwould make the background busier in above mentioned shooting environments.Sounds like you are suggesting that you get more DOF with the TC attached because you are now at f/8? Hence a busier background.I think that is quite correct. All a TC does is enlarge the image coming from the main lens. The f/8 is from loss of light from the enlargement process.One way of describing how a TC magnifies, is to say mounting a TC to a lens creates a "new" lens with a longer focal length. The longer focal length produces a narrower angle of view; more magnification. That new, longer focal length paired with the same physical aperture translates to an increased focal ratio (f-stop) from f/5.6 to f/8 and less light captured during a same-length exposure made at f/5.6. It also produces an increased depth of field compared, again to an exposure made from the same location, with the same physical aperture but a shorter focal length.I really can’t follow your explanation.Bottom line...  a 100mm f/2.8 with a 2x TC will show the same DOF as a 200mm f/5.6 lens.

Antal I Kozma wrote:michaeladawson wrote:Antal I Kozma wrote:Now, I do like the Tamron 150-600mm G2 for what it is. However, if a 600mm f5.6 smallish prime would come along I would adopt that for further increased AF speed, 1/3 stop more light gathering and less busy background rendering. On the other hand I would not step backwards to 500mm and lose 100mm reach. I also would not be happier with attaching a 1.4x converter to it and go down to f8. That would slow the AF speed andwould make the background busier in above mentioned shooting environments.Sounds like you are suggesting that you get more DOF with the TC attached because you are now at f/8? Hence a busier background.I think that is quite correct.All a TC does is enlarge the image coming from the main lens. The f/8 is from loss of light from the enlargement process.Mike, you might be right on this. I have not thought about this as you pointed it out.I simply went by my experience when shooting with the 500mm f4E FL with and without the 1.4x TC III. I have always felt that the background was busier when the TC was used, which is most often on the lens.It can simply happen that it was the actual scenery that made me feel that the background business increased.Thanks for pointing this out. Anyhow, I would be much much happier if Nikon would have developed a 600mm f5.6 lens. That definitely would become my most used birding and wildlife lens. Light and short and 600mm with a still good wide aperture, oh boy, it is a dream of mine.Someone else pointed it out that the 500mm f4 is the most popular in the exotic line up of Nikon's telephoto lenses. I definitely agree, I too opted for the 500mm lens. However, my reasoning was not that it is 500mm that would be my preferred focal length. I chose it because that lens was the one I could still use with a 1.4x converter hand held. 700mm f5.6 is not bad for reach and on the edge of my physical capability to carry it for hours in hand. I would not be able to do that with a 600mm f4. However, I could carry a light 600mm f5.6 for days in a row.I would sacrifice the reach of the 500mm + 1.4x for the weight and mobility advantages of a 600mm f5.6. However, I would not go back to 500mm only. As I mentioned earlier I rather carry my Tamron G2 and shoot at 600mm f6.3 when I need a lighter outfit for day long trekking.Now, I have no doubt that many will adopt this lens for their use. It is an "exotic lens", comes with bragging rights too. Then of course people who do not need the reach of a 600mm lens will take good use of this lens. When I said that I do not know why others would opt for this lens I was not clear enough. I meant those who do need more reach for something like tiny kinglets and warblers. For those the 500mm f5.6 might be less useful than a Tamron 150-600mm f6.3 G2.Best, AIKI see that I made a typo in my response.  I meant to say that is NOT quite correct.

michaeladawson wrote:Bill Ferris wrote:michaeladawson wrote:Antal I Kozma wrote:Now, I do like the Tamron 150-600mm G2 for what it is. However, if a 600mm f5.6 smallish prime would come along I would adopt that for further increased AF speed, 1/3 stop more light gathering and less busy background rendering. On the other hand I would not step backwards to 500mm and lose 100mm reach. I also would not be happier with attaching a 1.4x converter to it and go down to f8. That would slow the AF speed andwould make the background busier in above mentioned shooting environments.Sounds like you are suggesting that you get more DOF with the TC attached because you are now at f/8? Hence a busier background.I think that is quite correct. All a TC does is enlarge the image coming from the main lens. The f/8 is from loss of light from the enlargement process.One way of describing how a TC magnifies, is to say mounting a TC to a lens creates a "new" lens with a longer focal length. The longer focal length produces a narrower angle of view; more magnification. That new, longer focal length paired with the same physical aperture translates to an increased focal ratio (f-stop) from f/5.6 to f/8 and less light captured during a same-length exposure made at f/5.6. It also produces an increased depth of field compared, again to an exposure made from the same location, with the same physical aperture but a shorter focal length.I really can’t follow your explanation.Bottom line... a 100mm f/2.8 with a 2x TC will show the same DOF as a 200mm f/5.6 lens.Correct, it changes by 2 f-stops since 100mm / 2.8 = 36mm aperture, 200mm / 36mm = 5.6

michaeladawson wrote:Sounds like you are suggesting that you get more DOF with the TC attached because you are now at f/8? Hence a busier background.When you attach a TC you get a slower shutter speed offset by more dof than shooting with with (in this comparison) a 700mm lens.You still get less dof than shooting with a 500mm lens.

michaeladawson wrote:Antal I Kozma wrote:michaeladawson wrote:Antal I Kozma wrote:Now, I do like the Tamron 150-600mm G2 for what it is. However, if a 600mm f5.6 smallish prime would come along I would adopt that for further increased AF speed, 1/3 stop more light gathering and less busy background rendering. On the other hand I would not step backwards to 500mm and lose 100mm reach. I also would not be happier with attaching a 1.4x converter to it and go down to f8. That would slow the AF speed andwould make the background busier in above mentioned shooting environments.Sounds like you are suggesting that you get more DOF with the TC attached because you are now at f/8? Hence a busier background.I think that is quite correct.All a TC does is enlarge the image coming from the main lens. The f/8 is from loss of light from the enlargement process.Mike, you might be right on this. I have not thought about this as you pointed it out.I simply went by my experience when shooting with the 500mm f4E FL with and without the 1.4x TC III. I have always felt that the background was busier when the TC was used, which is most often on the lens.It can simply happen that it was the actual scenery that made me feel that the background business increased.Thanks for pointing this out. Anyhow, I would be much much happier if Nikon would have developed a 600mm f5.6 lens. That definitely would become my most used birding and wildlife lens. Light and short and 600mm with a still good wide aperture, oh boy, it is a dream of mine.Someone else pointed it out that the 500mm f4 is the most popular in the exotic line up of Nikon's telephoto lenses. I definitely agree, I too opted for the 500mm lens. However, my reasoning was not that it is 500mm that would be my preferred focal length. I chose it because that lens was the one I could still use with a 1.4x converter hand held. 700mm f5.6 is not bad for reach and on the edge of my physical capability to carry it for hours in hand. I would not be able to do that with a 600mm f4. However, I could carry a light 600mm f5.6 for days in a row.I would sacrifice the reach of the 500mm + 1.4x for the weight and mobility advantages of a 600mm f5.6. However, I would not go back to 500mm only. As I mentioned earlier I rather carry my Tamron G2 and shoot at 600mm f6.3 when I need a lighter outfit for day long trekking.Now, I have no doubt that many will adopt this lens for their use. It is an "exotic lens", comes with bragging rights too. Then of course people who do not need the reach of a 600mm lens will take good use of this lens. When I said that I do not know why others would opt for this lens I was not clear enough. I meant those who do need more reach for something like tiny kinglets and warblers. For those the 500mm f5.6 might be less useful than a Tamron 150-600mm f6.3 G2.Best, AIKI see that I made a typo in my response. I meant to say that is NOT quite correct.What a TC does, is increase focal length. Everything follows from that including an increase in f-stop, which is the ratio of focal length to aperture. Backgrounds can still be blown out at f/8, for example, if one is able to compose a shot placing the subject a good distance from the background. Unfortunately, most animals don't respond well to requests to, "move a bit to the right."

A recent summary of TCs, and see links on tests etc :-https://photographylife.com/what-is-a-teleconverterUp to a decade ago, a 5.6 telephoto prime was an acceptable optic - as in the 400 f5.6AIS IFED - a great prime. But this was before Nikon improved the IQ of its TCs. Now we have the benefits of  the TC Trio, conferring saved costs and weight. Today a f5.6 telephoto is a budget compromise UNLESS it has other benefits ie greatly reduced size and massThere are a couple of threads about the new patents for compact Nikkor PF primes. Where several of us agreed that a 400 f4E PF would be optimal. Not only thanks to its ergonomics, but, as I have argued elsewhere, for its higherTeleconverter Factor (TCF)of T3C0.5 - a 560 f5.6 with TC1.4; 680 f6.3 with TC17; 800 f8 with the TC2..... Unlike a  500 f5.6 or 600 f5.6.