[biz-engineer]

Hi there; does anybody know the exact aperture versus focal length on the DFA 150-450 ?

[Franc]

yes,,

[Adam]

Hi there; does anybody know the exact aperture versus focal length on the DFA 150-450 ?

F4.5 remains selectable up until around 250mm, after which F5.6 becomes the maximum. Clever move to keep it simple, IMO.

[biz-engineer]

Great, thanks Franc :-)
Could you please provide some max aperture values ( free of charge :-) )

---------- Post added 28-05-15 at 19:23 ----------

F4.5 remains selectable up until around 250mm, after which F5.6 becomes the maximum. Clever move to keep it simple, IMO.

Thanks Adam for providing this information.

[fredralphfred]

Great, thanks Franc :-)
Could you please provide some max aperture values ( free of charge :-) )

Are you saying that on zoom lenses the max. aperture adjustment isn't variable -- that it's stepped? If so, then how's the photographer to even know, unless he takes the lens apart & measures? And how far off can it get?

[Adam]

Are you saying that on zoom lenses the max. aperture adjustment isn't variable -- that it's stepped? If so, then how's the photographer to even know, unless he takes the lens apart & measures? And how far off can it get?

The user-selectable options are stepped, as always. But the wide-open light measurement and shutter speed is stepless in P mode.

[biz-engineer]

@Adam + fredalphfred: I was asking the max aperture to compare the max aperture of the DFA150-450 @300 with the f4 of the DA*300. To me, how much better the DFA150-450 is compared to the DA300 w/wo TC. Most of the time, the DFA150-450 will be used between 300 and 450, which basically is equivalent to the DA300 w/wo TC, but the DA300 has half the weight.

[fredralphfred]

@Adam + fredalphfred: I was asking the max aperture to compare the max aperture of the DFA150-450 @300 with the f4 of the DA*300. To me, how much better the DFA150-450 is compared to the DA300 w/wo TC. Most of the time, the DFA150-450 will be used between 300 and 450, which basically is equivalent to the DA300 w/wo TC, but the DA300 has half the weight.

Sorry -- from what you wrote earlier I thought you were looking for an absolute value in mm, which I thought meant you either knew or didn't think the reported f/stop value was accurate all the time.


Thanks for the clarification.

[Adam]

@Adam + fredalphfred: I was asking the max aperture to compare the max aperture of the DFA150-450 @300 with the f4 of the DA*300. To me, how much better the DFA150-450 is compared to the DA300 w/wo TC. Most of the time, the DFA150-450 will be used between 300 and 450, which basically is equivalent to the DA300 w/wo TC, but the DA300 has half the weight.

This is something that will have to be tested. The 150-450mm is pretty sharp as soon as you stop it down by half a stop, and it also provides the flexibility of a zoom which is a key consideration for a number of applications. However, it's heavy and the ergonomics are quite poor so my guess is that users will likely stick with the 300mm / 60-250mm unless they really need the extra reach, or if they want something for the FF.

[biz-engineer]

This is something that will have to be tested. The 150-450mm is pretty sharp as soon as you stop it down by half a stop, and it also provides the flexibility of a zoom which is a key consideration for a number of applications. However, it's heavy and the ergonomics are quite poor so my guess is that users will likely stick with the 300mm / 60-250mm unless they really need the extra reach, or if they want something for the FF.

For me, there's a dilemma. A long tele prime is ideal with an APS-C sensor because the prime usually outresolve the zoom and the APSC provide the crop factor + ability to crop when having a 24MPixels sensor for instance.

That being said, as we can see the super zooms work pretty well on FF because of the relatively lower resolution requirement and also higher iso capability of the full frame, but then it offers less reach.
The choice of the long zoom over the prime is closely related to the shooting conditions. For birding, focal length is never long enough, cropping often done, except that with proper hiding approach, a long lens is not required anymore but the flexibility of the zoom is then more valuable thanks to proper framing, and in the same situation a 300mm prime is also suitable. For larger animals or sports, the targets are larger, so that no heavy cropping is needed, in this case, the flexibility of a zoom is also an advantage.

Now, according to a pro safari photographer (Nikon user), the most used lens (>80% of shots) is the Nikon 200-400 f4 + APSC camera/or +TC on FF. The DFA 150-450 covers a bit more than this range.
But, IMO, the DFA 150-450 is not really for birding. However , for a safari in Africa, the DFA 150-450 seems to be the right lens.

[GeneV]

Why would the 150-450 not work for birding?

[biz-engineer]

Why would the 150-450 not work for birding?

Sorry, it's not that the DFA150-450 would not work for birding. It depends on the size of animals and ability to get close, because 450mm f5.6 is what it is and a TC added on this zoom at 450mm would not be as sharp as a prime + TC. In a hide, the 150-450 would be perfect, no need to add a TC. In fact I made a simple rule for myself: 50m/m @500mm. This means that for get a 1 meter wide subject sized at 1/3rd in the frame with a 500mm lens, you need to be at 50 meter worst case. If a bird is 20 cm in size, you need to be placed at 10 meters from the subject => you can only do this from a hide. The advantage of a very sharp prime lens is that it is possible to crop 50% without loosing too much quality, so the advantage goes to the prime. Now, if you have to photograph a 2 meters long bear, with a 500mm lens, you can be 100 meters away from the bear, which is not difficult to achieve (and more safe..). IMO, since I consider that I can crop more with a prime and birds are small, I consider a prime to be better suited for birding, and the DFA 150-450 better suited for larger subject but could also be used for birding with less ability to crop versus a prime.

[GeneV]

Sorry, it's not that the DFA150-450 would not work for birding. It depends on the size of animals and ability to get close, because 450mm f5.6 is what it is and a TC added on this zoom at 450mm would not be as sharp as a prime + TC. In a hide, the 150-450 would be perfect, no need to add a TC. In fact I made a simple rule for myself: 50m/m @500mm. This means that for get a 1 meter wide subject sized at 1/3rd in the frame with a 500mm lens, you need to be at 50 meter worst case. If a bird is 20 cm in size, you need to be placed at 10 meters from the subject => you can only do this from a hide. The advantage of a very sharp prime lens is that it is possible to crop 50% without loosing too much quality, so the advantage goes to the prime. Now, if you have to photograph a 2 meters long bear, with a 500mm lens, you can be 100 meters away from the bear, which is not difficult to achieve (and more safe..). IMO, since I consider that I can crop more with a prime and birds are small, I consider a prime to be better suited for birding, and the DFA 150-450 better suited for larger subject but could also be used for birding with less ability to crop versus a prime.

Have you actually tried it with the TC to know how much it degrades? There is not as sharp as.... which can be plenty sharp.

[rvannatta]

Have you actually tried it with the TC to know how much it degrades? There is not as sharp as.... which can be plenty sharp.

I've spent some time contemplating the trade offs of TC's vs. cropping in photoshop. After all one is cropping in the lens before the sensor and the other is cropping afterwards. There are a couple of variables:
1) shake: IT is not completely clear to me whether using a TC or photoshop cropping manages shake the best.

2) the second factor is distracting 'sideground'--- parts of the photo that you would crop may have different lighting or distance that disrupt the automated properties of the photo (color balance, exposure, focus) When
you optically crop these distractions never get to the sensor.

Additionally a factor that is all too often over looked is the minimum focusing distance. I think it is sort of universally agreed that "getting close" is a a great way to improve the quality and resolution of a photo.

A TC will eat F stops but doesn't extend the minimum focus value. this can be an important trade off.

[GeneV]

For birding with small birds, I usually end up with the TC and cropping. On the DA*300, I hardly notice the difference in quality, but the shot really isn't happening without the TC.