random78

random78

Joined on Jun 3, 2010

Comments

Total: 113, showing: 21 – 40
« First‹ Previous12345Next ›Last »
In reply to:

kayone: Math is wrong on the 42.5 caption, should be an 85mm f 2.4 equivalent

+1

Direct link | Posted on Feb 2, 2013 at 00:50 UTC
In reply to:

Frederik Paul: You can just hope that the 30/1.4 has the same quality than the 35/1.4. If so, it'll a clear winner and better suited for APS-C. The current version is quite mediocre at best, particularly wide open.

@TTMartin: The current version is great in the center but fairly weak in the corners. Wide open at 1.4 it is sharper in the center than canon 35mm 1.4L @ 1.4. However the corners are weak and don't improve much even when you stop down. Also while the center performance is great for f1.4, it does not become very sharp when stopped down. It is a lens which primarily shines in the f1.4-f2 range. If you routinely need to use these apertures then it is an excellent choice. If you mostly shoot stopped down or if you are looking for corner to corner sharpness, then it is not for you. It is far from being optically perfect but for those who need a fast normal lens for their APS-DSLRs, it is great performer. But yes I hope that they have improved the corners and stopped down performance - that will make it much more desirable as an APS-C normal lens.

Direct link | Posted on Jan 30, 2013 at 22:17 UTC
In reply to:

jquagga: So ... the 60 DN is the only real new lens. The others are the same lenses in new housings. Which Sigma has taken to announcing as "new".

Since everyone has to update to have the uh, stylish new exteriors I'll take all of the old lenses everyone will be binning.

30mm 1.4 is definitely a new optical design (old one was 7 elements in 7 groups with a maximum magnification of 0.09x. The new one is 9 elements in 8 groups with a 0.15x max magnification). Not sure about the 30mm and 19mm DN lenses, though Sigma states that these have also been optically redesigned.

Direct link | Posted on Jan 30, 2013 at 01:58 UTC
In reply to:

io_bg: The 30mm f/1.4 looks sexy. I'll stick with my cheap but great Nikkor 35mm f/1.8 though.

I liked my Nikon 35mm 1.8 when I had it. However it is a bit too long for my liking as a "normal" prime. 30mm is a bit wider and for me a more useful general-purpose FL. Plus the extra half stop of light and DOF control doesn't hurt either.

Direct link | Posted on Jan 29, 2013 at 22:13 UTC
In reply to:

Roman Korcek: So Sigma will offer a redesigned 30mm F/1.4 in addition to the new 35mm F/1.4? Is that not overkill?

@suave: It is all relative of course. Being 2.5" compared to 3.7" for the 35mm 1.4, it is much smaller. But yes it is still a fairly chunky lens - thats the curse of the fact that the APS-C cameras share the mount with full frame cameras. So even though 30mm 1.4 is a "normal" prime for APS-C, its construction has to be more like wide-angle DSLR lenses and hence the extra heft.

Direct link | Posted on Jan 29, 2013 at 22:07 UTC
In reply to:

Prime_Lens: Quite interesting.. but it is a total donkey doo doo.

I am sure it will make it stop faster.
More light concentration is more light concentration, after all.

Sharper? Revolutionary?
Nah~
All they are doing is slapping in a piece of convex glass to an existing adapter.
And every time you add more layer of glass to the lens, the IQ goes down, and becomes more prone to internal flare and ghosting. Because it creates yet another glass surface for light to penetrate or bounce off of.

It's a fool's gold guys..

"Every time you add more layer of glass to the lens the IQ goes down" - Right which is why all manufacturers design lenses with a single glass element. right? :)

You are right that having more glass can have an adverse impact on quality. But remember lenses themselves have anywhere from 5 to 20 glass elements. These large number of glass elements are needed to eliminate the aberrations and the glass used is high quality to give high IQ. So no adding glass elements does not always lead to "degradation", it can lead to improvements as well if it is used to reduce aberrations. This adapter is also a fairly sophisticated 4-element design and not just a single piece of cheap glass. Being a $600 adapter it can include high quality glass elements like original lenses (it might even have better glass than some of the cheaper lenses) and by reducing the aberrations as explained in the white paper, it is actually quite plausible that it improves overall quality.

Direct link | Posted on Jan 14, 2013 at 18:12 UTC
In reply to:

Timmbits: Quote: "This also promises sharper images compared to using the same lens with a simple, non-optical adapter, as the visibility of aberrations is reduced."

I am sure, that if any serious tests are done, this will turn out to be a crock of BS. It is a known fact that adapters with a lens increase chromatic aberrations. This is obviously more marketing spin than science.
Maybe I'm sounding a bit harsh... but for $600, which is the price of an apsc camera body, there is no excuse for marketing hype substituting physics!

I use a $20 adapter with no optics in it, and my 50mm f1.4 retains all it's glory in the results it produces.

Not necessarily. At the end of the day if the glass elements used in an adapter are as high quality as the one's used in the lenses themselves then it doesn't have to degrade quality. The loss mostly comes because the adapters use cheap glass elements. But here we are talking about a $600 adapter, not a $50 adapter so it could have high quality glass elements.

Unlike other adapters, with their adapter you don't just take the center crop of the larger FF image circle and throw away the "extra". Instead they are taking all the light from the larger image circle and projecting that onto the smaller sensor. Thats where they claim the improvement comes in. It sounds plausible though we don't know how true the improvements are in reality. Maybe it is just a marketing claim or maybe there actually is an improvement. But why don't we wait until the product has been tested and then pass judgement

Direct link | Posted on Jan 14, 2013 at 17:38 UTC
On CES 2013: Hands-on with Samsung NX300 article (150 comments in total)
In reply to:

jpr2: yet another MILC from Samsung with no built-in VF?
what a failure - it really starts to get tiring :( !!

Hmm I don't understand your comment because there is Samsung NX20 with a built-in EVF. The NX100/200/300 series and the NX1000 series are without the EVF and will likely remain that way in future as well. The NX10/20 is the series with EVF. So the next EVF model will likely be the NX20 successor whenever it arrives.

It is just like Sony and Olympus - only top-end model NEX-7/E-M5 have built-in EVF (and larger body). Mid-level and entry-level models like NEX-5N, E-PL5 etc don't have a built-in EVF.

Direct link | Posted on Jan 10, 2013 at 06:36 UTC
On CES 2013: Hands-on with Samsung NX300 article (150 comments in total)
In reply to:

gsum: "When it comes to quick 'grab shots', for example, touching the screen to focus is so much quicker than manually positioning the AF point".

Why is it quicker than pointing the camera at what you want to focus on and then using focus lock whilst framing? Can anyone on the planet get a one-handed grab shot without blur? The Gadget Show people couldn't and nor could I. Touch screens on cameras are a useless gimmick.

Samsung make excellent cameras and lenses but they need to concentrate on useful photographic features rather gimmicks. They also need to use metal for their lens bodies as the one area in which their cameras are weak is in their look and feel.

One man's gimmick is another's feature. I find touch to select focus point a useful feature on my NEX-5N and somewhat miss it on my NX200. I don't use the touch to focus all the time but there are times when I find it handy. Where I find it even more useful is as a focus aid for my landscape shots on tripod. It is so quick and easy to click on different parts of the scene to magnify them and check critical sharpness.

Also you don't need to shoot with one hand to use touch focus. I normally use my right thumb to select a focus point on LCD while still holding the camera with both hands. There are some cases when I have to take on hand off the grip to select the focus point, but even then I shift the hand back to the grip before taking the picture. I have never taken a one-handed picture when when using touch focus.

Direct link | Posted on Jan 9, 2013 at 21:50 UTC
On The DSLR Field Camera article (180 comments in total)
In reply to:

Roland Karlsson: @David - perfectly correct - the back, i.e. the camera has to move. There should be a mount on the front of the shift lens.

Moreover - whats wrong with just turn the camera around the nodal point and just stitch? Why this unnecessary shift lens?

I think the author addresses this point and says that you can do the same by using a pano-head instead of a shift lens. However for him the shift lens is more convenient. When you are stitching shots from wide-angle lenses, you need to be careful with making sure that the rotation is exactly around the nodal point or else you will have trouble stitching. With the shift lens no projection is needed to bring all the captured images to the same plane - the images are all already aligned and in plane and stitching is a straightforward task. Plus less gear is needed

Direct link | Posted on Dec 26, 2012 at 21:30 UTC
On The DSLR Field Camera article (180 comments in total)
In reply to:

peevee1: Very interesting article.

I have a question.

Wouldn't use of Nikon D800 with Nikon 14-24/2.8G at 14mm f/11 at hyperfocal (just 2 ft) give you the same result in a single shot? Given how much you overlap and crop out, and the excellent performance of the 14-24 lens at f/11, with everything in focus from 1 ft on. And with 14EV of DR to work with at base ISO, you hardly need any HDR, just a right curve.

Don't expect to get everything in sharp focus from 1ft to infinity using the hyperfocal distance. You must keep in mind that the hyperfocal distance calculators assume a specific output size - typically 8x10. The hyperfocal calculation is simply saying that when viewed at that output size, the details from 1ft to infinity will be "sharp enough". When you will look at your image at 100% pixel level or print it at a big size, you will find out that the details don't seem that sharp. Also the notion of sharp enough is subjective because the degree of sharpness needed depends on the subject matter as well as on what each user considers to be sharp. The calculators assume a certain mathematical threshold for what should be considered sharp enough. The resulting numbers give a good estimate for things like portraits at normal viewing sizes. However they are not suitable when you are looking for critical sharpness in small details.

Direct link | Posted on Dec 26, 2012 at 20:24 UTC
On Just posted: Sigma 35mm F1.4 DG HSM lens review news story (182 comments in total)
In reply to:

Ivan Lietaert: "a top notch fast 35mm autofocus prime without breaking the bank"
Priced £900, the author obviously must be making a fortune writing for DPreview! This lens is priced at a working man's monthly income. I wouldn't call that cheap! Please think twice before you write this kind of thing!

Sure, I am glad you are happy now :)

Direct link | Posted on Dec 21, 2012 at 20:08 UTC
On Just posted: Sigma 35mm F1.4 DG HSM lens review news story (182 comments in total)
In reply to:

Ivan Lietaert: "a top notch fast 35mm autofocus prime without breaking the bank"
Priced £900, the author obviously must be making a fortune writing for DPreview! This lens is priced at a working man's monthly income. I wouldn't call that cheap! Please think twice before you write this kind of thing!

I am sure there are plenty of people who won't or can't spend even € 100 on just a lens or a few hundred pounds on a DSLR. The point is that this comment is in the context of people who are advanced enough into their photography hobby to be looking beyond the $400 35mm f2 lenses. For many of them the jump from a $400 35mm f2 to a $1600 35mm 1.4 is not viable. However the sigma at $900 becomes much more in the realm of affordability. Anyways we are nitpicking here.

Direct link | Posted on Dec 21, 2012 at 20:07 UTC
On Just posted: Sigma 35mm F1.4 DG HSM lens review news story (182 comments in total)
In reply to:

Erik Johansen: For that price it should got a 100% score.......

Ahhh. I must admit I interpreted Erik's post the same way as Clint did. Looked to me that Erik is saying that "such an expensive lens should have been good enough to get a 100% score". But from your comment it seems Erik meant to say that "considering the high performance this lens is achieving at such a low price, dpreview should have given it a 100%".

Direct link | Posted on Dec 21, 2012 at 19:28 UTC
On Just posted: Sigma 35mm F1.4 DG HSM lens review news story (182 comments in total)
In reply to:

gsum: I'm a bit surprised to see so much CA in the real world examples in such an expensive lens, particularly at this focal length. Also, DPReview, why the excessive sharpening?

A D800e would have given this lens a better real world test as there would be no anti-alias smearing.

CA is common with all ultra-fast lenses including much more expensive lenses like Cnaon 85mm 1.2L. Remember ultra-fast lenses push the optics to the limit and do suffer from such compromises. Sigma actually does better than many other fast lenses.

Direct link | Posted on Dec 21, 2012 at 18:47 UTC
On Just posted: Sigma 35mm F1.4 DG HSM lens review news story (182 comments in total)
In reply to:

facedodge: If it weren't for the onion bokeh, this would beat the 35L.

The reason you never noticed it in the 35L is that in most cases it won't be visible unless you look at your image at 100%. Unless you have some lights which take up an unusually large portion of your image frame, you just won't see it in normal viewing. So yeah might be a serious issue for some but nothing to worry about as far as I am concerned. A 35mm 1.4 lens is an extreme design and always requires compromises. You will never find any 35mm 1.4 lens which will be perfect without any flaw. Based on the reviews so far, the Sigma is as close to perfect as have been seen for a 35mm 1.4 lens so far. So you can either choose to worry about a problem which may have no practical concern for you in your photography or enjoy a great lens.

Direct link | Posted on Dec 21, 2012 at 18:34 UTC
On Just posted: Sigma 35mm F1.4 DG HSM lens review news story (182 comments in total)
In reply to:

Ivan Lietaert: "a top notch fast 35mm autofocus prime without breaking the bank"
Priced £900, the author obviously must be making a fortune writing for DPreview! This lens is priced at a working man's monthly income. I wouldn't call that cheap! Please think twice before you write this kind of thing!

Quality photography gear is expensive and you have to look at the price in that context. Compared to the Canon/Nikon/Sony versions at $1500-1600 and the Zeiss at $1800, the Sigma at $900 is surely a much more affordable option.

Direct link | Posted on Dec 21, 2012 at 18:25 UTC
In reply to:

Entropius: There are a lot more things to a lens's performance than a one-dimensional measurement. What does this scheme make of a lens like the Panasonic 14/2.5, which is extremely sharp but has high chromatic aberration? What about the Canon 70-200/2.8 mk1 at 200/2.8, which has poor microcontrast but resolves a good amount of detail? The high sharpness and resolution, but bizarre bokeh, of the Zuiko 50-200?

What about a classic lens like my Olympus OM 50/1.8, which is surprisingly highly-resolving wide open in the middle of the frame (great for portraits) but without the high acutance of modern asphericals, and with a strong dropoff in sharpness toward the edge?

There's a whole lot more to a lens's performance than one number. That's why the old DPReview lens reviews were great, with the little checkerboards: you can see for yourself what the point spread function at different places in the frame is.

> It's a weighted average across the field for the "best" aperture.

Right. And for a zoom lens it is at whichever arbitrary focal length + aperture combination gave the best result for that lens. So a lens gets good score because at some particular combination of focal length and aperture, using some specific unknown weighting of center and corner sharpness it performs well . I wonder how could you consider it a useful measure despite the comparison being so arbitrary. As an example under this measure Canon 24-105mm f4 and Canon 18-55mm IS II have the same P-MPix Score on a 7D.

Direct link | Posted on Dec 18, 2012 at 09:46 UTC
In reply to:

Erik Magnuson: I think this score will correlate pretty well with lens sharpness in general, i.e. a lens with a P-Mpix 15 (of 18) will be noticeably better than a lens with a score of 8. However, it may not correlate as well for small differences, e.g. a score of 14 and a score of 15 may mean lenses that merely have different strengths (i.e. center vs. edge, best vs. wide open performance) where the weighting used does not match the user preference.

If a user merely wants to know "what's an excellent vs. merely good lens", then this number will be useful. Buying the lens with the highest number is rarely going to be "wrong" but it may not be optimal. If you want to know "what the best lens for 35mm f/2 corner to corner" then this number will not be as useful. Digging down into the detail graphs may help, but if you have specific questions you should not expect average numbers to be the answer. Also remember YMMV so small differences in measurements may not be significant in field use.

And I disagree with every site that does that :) including dpreview's percentage scores for cameras which I think are even more useless than DxoMark's scores. If I am lazy when reading say dpreview or photozone, I just read their conclusion paragraphs, but not the scores which can be safely ignored. Also with dpreviw and photozone the score comes at the end after the whole review, as sort of a summary. DxoMark on the other hand emphasizes its scores and de-emphasizes the detailed results which this score is based on. Also by the way not every website does that - for example imaging resource, dcresource or steves-digicams do not have any scores for cameras, even though these websites do a lot more point and shoot reviews as well. Similarly lenstips or slrgear do not have any lens scores. They expect their readers to read the review not reduce the whole review into one meaningless number.

Direct link | Posted on Dec 18, 2012 at 02:24 UTC
In reply to:

Erik Magnuson: I think this score will correlate pretty well with lens sharpness in general, i.e. a lens with a P-Mpix 15 (of 18) will be noticeably better than a lens with a score of 8. However, it may not correlate as well for small differences, e.g. a score of 14 and a score of 15 may mean lenses that merely have different strengths (i.e. center vs. edge, best vs. wide open performance) where the weighting used does not match the user preference.

If a user merely wants to know "what's an excellent vs. merely good lens", then this number will be useful. Buying the lens with the highest number is rarely going to be "wrong" but it may not be optimal. If you want to know "what the best lens for 35mm f/2 corner to corner" then this number will not be as useful. Digging down into the detail graphs may help, but if you have specific questions you should not expect average numbers to be the answer. Also remember YMMV so small differences in measurements may not be significant in field use.

> "And what happens when they do this? They get a good lens"

They can also be paying a lot more than needed just to get a lens which "scores" better, even though for their uses it might not even be the better lens.

>Can you suggest anything better that lazy users should use as a guide?

What Entropius said - don't be lazy. I don't think promoting laziness by making it easy to make misinformed decisions is a good idea. We have already seen this with DxoMark sensor scores where people on forums talk about one sensor being rubbish because it is 10 points lower than the other one on DxoMark, even though looking at the detailed graphs tells a very different story. The issue with "scores" is that you always want the one with the highest "score" and feel dissatisfied with anything with lower score. Whereas by looking at detailed reviews you actually understand which product better meets your needs.

Direct link | Posted on Dec 18, 2012 at 01:42 UTC
Total: 113, showing: 21 – 40
« First‹ Previous12345Next ›Last »