Bad Sigma 17-70 macro OS?

Started Jul 11, 2012 | Discussions thread
Malvin Camina
New MemberPosts: 5
Like?
Re: Bad Sigma 17-70 macro OS?
In reply to Tucabert, Jul 13, 2012

Hi Albert,

I've been using these Lens for some time now. I have no complain except that it does not peform well in low light condition. I agree also that most who complain are canon users not just from this from this forum site but also in other sites. But I must say that there are number of Nikon users who got delima upon using sigma lenses. Here in Manila we are not afraid of buying it from a third party vendor or buy and sell sites becase we have a official distributor who does Lens Callibration in relation to focusing problem. Another problem depending on situation is that when you are shooting too far away from the subject it is difficult to focus properly. Although by means of trial and error I manage to cure that. You have to consider when, what, where, and how to shoot wide at 17mm and tele 70mm aswell as their respective aperture to obtain the right sharpness and focus. Your distance to subject in relation to the lens you're using is big factor. I just recently learned that there is an important technical aspect involved in all diff lenses. You must learn its in depth specs, needs, and purpose. Let me share you one of the response from our group here in manila about "Focusing and Sharpness".

-- hide signature --

1. Lens Sweet spot is between f/5.6-f/8 but there are some lens that can go f/16. This will not also depend on the lens but also the type of camera sensor (FX or Crop). Generally in you are within this range, everything will be clear and sharp but there will be a peak sharpness this is also called MTF or Modulation Transfer Function.

2. The distance of the model to the background will affect the sharpness of the image if the model and the background is beyond the DOF you are aiming for, which is controlled by the Aperture. The narrower the Aperture the DOF in focus also increases. As the aperture becomes narrow the need for more light also increases. If the light is increased the cast shadows becomes smaller because light starts to envelop the model, without the right speed and ISO to expose your model to 18% grey (some says 12%), the image will be over exposed. If you have an Android Phone, you can download DOF calculator apps for free over at the Play Store. To play by hunch as to what combination of light goes with right ISO and speed could possibly be done. But if you will be mixing 3 or more light source you will have a hard time doing so without a light meter. Initially you will balance 2 light sources, ambient and flash to give you the flash-ambient ratio but if you have more than one flash that will serve as kicker, background and hair light, this will waste a lot of time with out light meter.

3. How sharp is sharpness, is not just the clarity of the image but the artistic value it represent. If you have a blurry background the subject in focus would be sharp, but does it justify the background being blurred or should it be in clear focus as well would depend on the photographer taking the picture. Bokeh is nice, but not all the time. Depending on the effect you wants to achieve to give artistic heights in your composition. How would you develop this...by looking at more and more pictures, some are born with these eyes, some have to develop them.

4.The camera would do what a camera does, that is to take pictures. But what makes a picture a photograph is the duty of the photographer. A photograph is a picture with a story, with expressions, emotions, purpose, aim, statement. Any 10 year old that can hold a camera can take a picture. Some would think that models just pose and might not play a significant role in the development of a photograph, if you think the same...you will be wrong. You see, models/ subjects, conveys emotions, statements more clearly and right to the point. Say happiness, sadness, pitiful homeless people that brings out the viewers feeling of empathy. These are emotions that carry a story, hand gestures, gazing eyes, fluff of the hair, colors, all these convey a story, of anger, of love, sensuousness, playfulness. All of these plays a role in developing your composition. Even bare foot feet plays a role in telling a story, if you blur these elements just because for bokeh, you will loose Drama and without Drama your picture can not be called Photograph. Just like in painting, a painting is different from Fine Art Painting. Anybody can paint a picture, but not everyone can paint an Art.

There is no way for you to improve unless you shoot more pictures and look at even more pictures. Since you have live subjects to shoot, learning how to pose them will give character to your work, and from there you will understand when an element is acceptable to be blurred and when it is not. HTH.

--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

If you're going to buy the Lens don't get frustrated. If you know of someone where you could borrow it for test fire the better. Learn how to maximized the lens at its best performance anc cope up with its limittations. Better if there is someone who callibrates Sigma lenses in your area if there is a focusing problem. Otherwise save your money and get the Tamron 28-75mm f/2.8 . I'm sure with the you only have it's worth it. Just remember Sigma 17-70mm is not that expensive but again, YOU GET WHAT YOU'VE PAID FOR.

Malvin Camina
Backpacker|Nocturnal|Photographer
I am Nikon

Reply   Reply with quote   Complain
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow