70-300MM for D7100

[ajohnw]

"The Sigma / Tamron versions may be comparable especially with a converter on. From the reviews I have seen they have more fall off to the edges than the Nikon lenses. I also don't know if Tamron have maintained the quality on the newer VC lens but these I believe are around £1000"

Thanks for your answer John. It raise another point I would like to ask for: is the quality of a lens + converter as good as the equivalent lens only? In other words does the converter keeps the quality of the lens or seriously flaws it? PhliT

i was referring to the 70-200mm F2.8 route on that. I bought my 2x converter used of some one who tried to use it on the 70-300mm and AF doesn't work from part way through the focal range. The 1.4x may be ok on it.

The problem with converters is that lenses have errors that spoil the performance. The converter multiplies these as well and will add it's own. The good aspect is that they don't use the edges of the normal frame but over all there is a loss so a great lens is turned into a poorer one. This review shows the effect but on a D200. A newer camera should come up with bigger numbers.

http://www.photozone.de/nikon--nikko...report?start=1

The way to look at this prime is to look at the 70-300mm test I posted earlier and notice that the resolution is lower at 300mm than other settings. The prime should be better so adding a teleconverter is likely to produce better results than the zoom at 300mm. There are sometimes comments on bird forums about not using converters on zooms but people do get decent results. I always wonder about the distance they were shot at as it matters. Looks like the Nikon 70-300mm doesn't provide it or Adobe corrupt it. Of the 70-300mm I would probably go for the Nikon. On the other options I just can't make my mind up and am playing with m 4/3 mostly. May as well show some results from that, Canada goose. 100% crop from a camera jpg. It's somewhat under 1/2 the frame width.



PP's to web size from the jpg - - playing with a PP sharpening method so some what over done. ? Robin

I could probably bring all the white back from raw.



Shot at 228mm so about 456 full frame, 300mm crop. I'm not convinced that a crop camera would give better results so really need to do more shooting with the nikon. There is a catch in this area. In principle anything shot using a full frame lens on a crop body could be cropped out of a full frame shot. Same applies to m 4/3. The only way round this is higher resolution lenses on the smaller sensor sizes. Test suggest that the 75-300mm Oly lens may be better than say the 70-300mm full frame lenses on a crop body. It's hard to find a site where it can be compared but the sigma 70-300mm comes up with figures like 2400 lp/ph, the 55-300mm Nikon 2100 lw/ph and the Oly 75-300mm 2,700 lw/ph. These are the number of lines that can be resolved on the respective sensor size. Having too many pixels on the sensor for this level of resolution and it wont really make much difference to the results. All just a thought. I decided to try both within reason cost wise and try and find out myself. I'm sort of concluding m 4/3 wins but if ISO is very important buy a full frame that doesn't have too high a pixel count otherwise crop could be broadly similar.


John
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[The Blue Boy]

Another thumbs up for the Nikkor from me. I adore this lens.

D300s, f5.3, iso 200, @220mm, manual;



D300s, f5.3, iso 400, @195mm, Aperture Priority;



The down side to this lens that I've found is that it's not that good when the light starts to drop. But that could be said of many lenses...

[Acorn]

I share many of the thoughts expressed in this string of postings. I have a Nikkor 70-300 VR that I use in conjunction with a D7000 for some of my wildlife photography. I've no hang-ups about the lens and cannot think of an instance when it has not delivered a razor-sharp image. In the end it boils down to your personal preference or how deep your pocket is.

[PhilT]

Another question please: is there a point to put aFX lens on a DX camera? Does it add something?

[John 2]

There are probably two good reasons for doing this Philippe. The first is that a DX camera will only use the centre of the coverage that the FF lens is designed for. Fall off in quality generally occurs towards the edge of this area and so a DX camera doesn't see that fall off. That's a factor but it's not generally a big problem even if you are using an FX camera because most people crop their images anyway. The second reason is that if you ever contemplate going full frame, it will be less expensive because you won't have to replace the FF lenses that you already have.

[Shadowman]

So does anyone use these SQF charts when rating a lens and if you do, do you use print size as a verification of your lenses acceptability.

http://www.popphoto.com/gallery/sqfs...es?i=70149&s=3

[Saorsa]

I think that a third reason is that the laws of physics dictate lens size to a large extent. Getting f2.8 or 1.8 takes some diameter depending on Focal Length. At some point, there isn't enough difference to make a dedicated DX (or CX) lens worthwhile.

The Nikkor 35mm f1.8 for the FX cameras is

$600 FX Lens
Approx. 2.83 x 2.81" (72 x 71.5 mm)
Weight 10.76 oz (305 g)

$200 DX Lens
Approx. 2.8 x 2.1" (7.11 x 5.33 cm)
Weight 7.05 oz (200 g)

32mm f1.2 CX lens
Approx. 2.58 x 1.85" (65.5 x 47 mm)
Weight 8.29 oz (235 g)

Considering build quality that's pretty much a wash