[repaap]

The thing is that with DFA 28-105 you really want to shoot one or two stops closed down. It is good enough for wide open but not across the whole zoom scale. Especially when you go past 50 mm. and that is to be expected. With 70-210 one might expect good performance even from f4. That goes to 70-200/2.8. That is the main reason why one buys them and uses them even if they are bigger. Only 150-450/4,5~5,6 has good/great performance at widest aperture, and it is not fixed, as one can see. But price is higher. I’d not expect that kind of performance from this zoom. I hope it catches up by f8-11. And is good enough at centre wide open for some close up counter with birds.

[fsge]

Surely a new 70-300 would be just as short at 300...

crop factor...

[Serkevan]

The thing is that with DFA 28-105 you really want to shoot one or two stops closed down. It is good enough for wide open but not across the whole zoom scale. Especially when you go past 50 mm. and that is to be expected. With 70-210 one might expect good performance even from f4. That goes to 70-200/2.8. That is the main reason why one buys them and uses them even if they are bigger. Only 150-450/4,5~5,6 has good/great performance at widest aperture, and it is not fixed, as one can see. But price is higher. I’d not expect that kind of performance from this zoom. I hope it catches up by f8-11. And is good enough at centre wide open for some close up counter with birds.

I'd argue that the 28-105 at 105mm and f/5.6 is perfectly usable at closer focus, for example for portraits and such - center sharpness is very good. If you are focused at infinity it's a different story, but at f/8 or f/9 it's already sharp as a nail and you probably want the deeper DOF anyway for landscapes.

The 150-450 or 70-200/2.8 are a great example of what it takes to get to that level of performance: we're looking at 2 kg (1.8 in the 70-200/2.8) behemoths that come in at ~2000€ apiece. A 70-300 lightweight (presumably, at least) zoom fills a completely different purpose; as you say, it would be perfectly acceptable to have optical compromises if that means the lens is lightweight and fast-focusing.

---------- Post added 06-08-20 at 04:31 AM ----------

crop factor...

A 300 mm lens is a 300 mm lens, regardless of sensor format.

[Paul the Sunman]

crop factor...

Nooooo! 300 is 300 is 300 .... On an APS-C camera they will both have the same angle of view at 300mm.

[repaap]

I'd argue that the 28-105 at 105mm and f/5.6 is perfectly usable at closer focus, for example for portraits and such - center sharpness is very good. If you are focused at infinity it's a different story, but at f/8 or f/9 it's already sharp as a nail and you probably want the deeper DOF anyway for landscapes.

The 150-450 or 70-200/2.8 are a great example of what it takes to get to that level of performance: we're looking at 2 kg (1.8 in the 70-200/2.8) behemoths that come in at ~2000€ apiece. A 70-300 lightweight (presumably, at least) zoom fills a completely different purpose; as you say, it would be perfectly acceptable to have optical compromises if that means the lens is lightweight and fast-focusing.

---------- Post added 06-08-20 at 04:31 AM ----------

.

Yes, And perfectly usable depend on many things. If i shoot with DFA*70-200 and also use DFA 28-105 in same place or different Pov. I want to have comparable Image quality. I'll stop DFA 28-105 down, or change to DFA*70-200 if I need more narrow Dof(or FA 31 or...). Images does look quite similar around f8, Bokeh is more ugly from DFA 28-105 compared to DFA* that there is not actually much benefit to try to shoot it wide open. It is usable, but it is not as good. I believe, my point is that. Main thing is that you are able to get them looking the same, but it needs to be stopped down. Especially if I use my strobes. DFA 28-105 can even survive pixel peeping at there, not too much, but it can. That is IMO what make it to still stay in my camera bag. I hope for something similar from this new lens.

I liked my DA 55-300 WR, it is just that now with K-1 one(me) want more. it says in this patent that it has been designed for sensors with 30MP and more. That is really promising also.

[Serkevan]

Yes, And perfectly usable depend on many things. If i shoot with DFA*70-200 and also use DFA 28-105 in same place or different Pov. I want to have comparable Image quality. I'll stop DFA 28-105 down, or change to DFA*70-200 if I need more narrow Dof(or FA 31 or...). Images does look quite similar around f8, Bokeh is more ugly from DFA 28-105 compared to DFA* that there is not actually much benefit to try to shoot it wide open. It is usable, but it is not as good. I believe, my point is that. Main thing is that you are able to get them looking the same, but it needs to be stopped down. Especially if I use my strobes. DFA 28-105 can even survive pixel peeping at there, not too much, but it can. That is IMO what make it to still stay in my camera bag. I hope for something similar from this new lens.

I liked my DA 55-300 WR, it is just that now with K-1 one(me) want more. it says in this patent that it has been designed for sensors with 30MP and more. That is really promising also.

Oh, of course neither the 28-105 nor the 55-300 have the same level of quality (in sharpness, aberration control, bokeh, you name it) as the Star glass - but a K-1 with both those lenses weighs less than just the 70-200/2.8 (not to mention that both lenses together cost half of the Star...), and that's reason enough* to use the lighter lenses IMO - not to substitute, but for situations where weight is important. I also expect the 70-300 to be similar in quality to the 28-105, as a better option for FF than the 55-300 .


*If I go on a day hike (say, a pretty typical one would be 15-20km with ~500m elevation gains) I'll carry K-1, 28-105, M20/4 and maybe a 70-210/4.5. Total weight is 2.3 kg. I don't see myself carrying the holy trinity of zooms, let alone the 150-450, too much weight once you put water and food in the equation.

[repaap]

Oh, of course neither the 28-105 nor the 55-300 have the same level of quality (in sharpness, aberration control, bokeh, you name it) as the Star glass - but a K-1 with both those lenses weighs less than just the 70-200/2.8 (not to mention that both lenses together cost half of the Star...), and that's reason enough* to use the lighter lenses IMO - not to substitute, but for situations where weight is important. I also expect the 70-300 to be similar in quality to the 28-105, as a better option for FF than the 55-300 .


*If I go on a day hike (say, a pretty typical one would be 15-20km with ~500m elevation gains) I'll carry K-1, 28-105, M20/4 and maybe a 70-210/4.5. Total weight is 2.3 kg. I don't see myself carrying the holy trinity of zooms, let alone the 150-450, too much weight once you put water and food in the equation.

That is true if one decide to carry a big lens still, there is no complaining afterward. Especially now when there will be light option from Pentax also.

[bertwert]

crop factor...

Off topic to this thread, but I just want to clarify this. Pretend you never heard the term.

300mm is a set property of the lens. It does not change with whatever sensor you use, be it FF or APS-C. Now, as APS-C sensors are smaller than FF sensors, they only see a portion, or crop, of the FF sensor. So the field of view is 1.5x times as long. It's the same idea as taking an image with a FF camera and cropping it in post. The lens has no effect here. If you only shoot APS-C, or only shoot FF, forget this, as it really means nothing. Just get familiar with what focal length gives what field of view with your camera.

The reason you get 'FF lenses' and 'APS-C lenses' is because of the image circle the lens projects - as FF sensors are bigger, a lens designed for FF needs to project a larger image for the sensor to capture. APS-C lenses generally project a smaller one - which can also help keep the size of the lens down. Because of this, you can use FF designed lenses on APS-C without a problem, as it projects an image large enough to cover the sensor. The other way around does not always work, as the image projected by an APS-C designed lens is often smaller than the FF sensor, resulting in vignetting or very poor corners.

[stevebrot]

Not sure for the more tele zooms, but here's a few common 'kit' lenses:





It'd be nice if this info was easily available for all lenses.

Of course, the values, both aperture and focal length, are those reported by the lens. It is hard to say what the actual aperture is, but is probably close.* As for the info being easily available...it's all in the EXIF, at least for AF zooms.


Steve

*Ironically, it makes little difference from a TTL metering point of view. Measurements are always wide open and stop down is always relative to maximum; there is no set actuation for f/7.1, for example, that applies to all lenses.

[normhead]

Images does look quite similar around f8, Bokeh is more ugly from DFA 28-105 compared to DFA* that there is not actually much benefit to try to shoot it wide open.

I never hesitate to shoot my 28-105 wide open. It's just not an issue.
If you're talking the difference between ƒ2.8 and ƒ 5/.6 then it's a no brainer.
2.8 bokeh is smoother on the same lens, forget about between lenses.

[repaap]

I never hesitate to shoot my 28-105 wide open. It's just not an issue.
If you're talking the difference between ƒ2.8 and ƒ 5/.6 then it's a no brainer.
2.8 bokeh is smoother on the same lens, forget about between lenses.

I suppose that this is again one of these matter of taste things. It is combination of both of those things. Yes, I get better bokeh with * lens compared to this @5,6. But DFA 28-105 general performance is so good stopped down a bit, that if I have DFA* at hands(or other bokeh machine for wider end I’ll use that, then again if sharp image with nice colour and big DoF is needed no point to change lenses. Sure, it can be shot wide open(28-105).

[normhead]

I suppose that this is again one of these matter of taste things. It is combination of both of those things. Yes, I get better bokeh with * lens compared to this @5,6. But DFA 28-105 general performance is so good stopped down a bit, that if I have DFA* at hands(or other bokeh machine for wider end I’ll use that, then again if sharp image with nice colour and big DoF is needed no point to change lenses. Sure, it can be shot wide open(28-105).

That just makes me curious, have you ever done a check in your PP software to fid out what percentage of you images are taken at ƒ2.8 or under for that "smooth bokeh"? For me it's 44 images out of 1300 images.

I have many 2.8 lenses, but not many 2.8 images. For the most part, living without 2.8 glass wouldn't affect me very often. I'm curious as to what those numbers look like for the average shooter. It makes me wonder how many have paid for capability they don't use.

Life is always full of unanswered questions.

Another interesting thing of note, looking at telephoto lenses, to check out the ƒ5.6 vs ƒ8 thing, I note that from 250mm, the diffraction limit seems to get pushed back from between 5.6 and8 for shorter lenses to ƒ8 to ƒ11 in the longer ones. I might have to look into that more.

[Wheatfield]

crop factor...

Oh dear.

[TwoUptons]

That just makes me curious, have you ever done a check in your PP software to fid out what percentage of you images are taken at ƒ2.8 or under for that "smooth bokeh"? For me it's 44 images out of 1300 images.

I have many 2.8 lenses, but not many 2.8 images. For the most part, living without 2.8 glass wouldn't affect me very often. I'm curious as to what those numbers look like for the average shooter. It makes me wonder how many have paid for capability they don't use.

I've never counted, but I really like the look of my 50 mm f1.4/f1.7 lenses at about f2.0... (and they're all "classics")
The dreaminess is mostly gone, and they're sharp enough for most of what I need, yet still give nice subject separation.

With the Rokinon 85mm f1.4, f2.0-2.8 has about the same effect, plus it gives me enough depth of field to get the eyes in focus even if I wobble a little...

But in my case, nothing f2.8 or faster at any focal length over 135 mm

-Eric

[normhead]

I've never counted, but I really like the look of my 50 mm f1.4/f1.7 lenses at about f2.0... (and they're all "classics")
The dreaminess is mostly gone, and they're sharp enough for most of what I need, yet still give nice subject separation.

With the Rokinon 85mm f1.4, f2.0-2.8 has about the same effect, plus it gives me enough depth of field to get the eyes in focus even if I wobble a little...

But in my case, nothing f2.8 or faster at any focal length over 135 mm

-Eric

Personally I was surprised. For my macros I always start shooting at 2.8 then 4,8 ,16 with some variation sometimes 4,5.6.8.11, 16. I have looked at many 2.8 images, but a great number of them have been discarded and are no longer on my drive. Yesterday I came home with 23 images at least half with 2.8 versions but not one selected as the best image.

That and the only test image being acceptable at ƒ1.4. The one I took just to see what the best case scenario was bokeh wise on my DA* 55 1.4.

And look at the test chart for the DA*60-250


Form 60-135 it's what I expected ƒ5.6 is the sharpest ƒ-stop.

But at 200mm and 250mm ƒ8 is the sharpest ƒ-stop, the diffraction limit appears to get pushed back with the length of the lens. After 200mm ƒ8 is sharpest and also has the sharpest edges. As indicated, I'm not familiar with the reasons for this.