September 01, 2014, 07:51:26 PM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - heptagon

Pages: 1 ... 6 7 [8] 9 10 11
You linked to scaled versions of the images but i found the originals in your gallery  :)

It's pretty hard come to a definite conclusion regarding the quality. Also at the shot with the 2x converter a cloud is on the main tower reducing contrast and it seems like some kind of noise reduction is employed. Additionally there may be air turbulences and slight focusing errors etc.

I think most people will be happy with the 1.4x extender on any tele lens F/4 or faster but the 2x extender is only a compromise.

A 50mm shot for comparison. Try scaling it :)

That's quite impressive!

You are right, stopping down  stop may improve the image quality. The 70-200 ii i dont know, but with the 300 2.8 i nearly never had lighting conditions where i get an improvement by stopping down, as motion blur is worse than "lens softness" or "converter softness".

The 70-200 II with 2x extender just doesn't look right at F/5.6 at F/8 there is a big improvement. It's about on the sharpness level of the 400 L F/5.6 when shooting between F/5.6 and F/8.

As far as i know the 300 F/2.8 is already a very sharp lens wide open. But it's hard to actually find the reason for softness at long focal ranges as focusing problems and various vibration sources also play a role.

For me a subject in direct sunlight and the lens on a monopod with IS on and the camera (550D) on iso 400 max worked pretty well but only half of the shots are satisfying. Selecting a higher iso destroys detail and you cannot sharpen the image anymore without adding a lot of grain. So the situations where using a TC actually makes sense are pretty limited.

The 70-200 L IS II with 2x III TC would certainly work but you will need to shoot at f/8 and need lots of light. AF performance also depends on the light level. I don't know of a direct comparison between this combination and the 400 F/5.6 and the 100-400L or the 300L F/4 + 1.4x TC. If you get a good sample of each one, the image quality at F/8 will be satisfying and the prices are in a comparable range.

But long focal lengths are very hard to master and due to light constraints you may not be able to shoot at F/8 anyways and need something faster. Then it might be considerable to start with the 1.4x TC for the 70-200 you already have. This combination is certainly very good at F/4 already.

Using a crop camera is always a better choice than a teleconverter or a mediocre lens.

Only if you can't get further with cropping you might consider getting a longer lens. Before you go for the 400L F/5.6 check if you can live without IS. The 300L F/4 and 100-400L also only have mediocre IS compared to the 70-200 you have.

If needed i use the 2x iii which gives amazing results in good light and for slow moving subjects. With the 2x 8x more shutter time is needed, 4x because of 2 stops less opening and 2x stop because of doubled focal lenght. from my experiance its better to cop a picture than pushing up iso by 3 stops, as iso 1600 looses lots of detail compared with iso 200 on the crop body.

For the 70-200 L IS II you could add another stop to the light requirement for stopping down from f/5.6 to f/8 with extender instead of useable f/2.8 without extender. So that would be 16x more light required. However there might just be enough light for all directly sun-lit subjects. If you can shoot at f/16 without extender, you can shoot at f/8 with extender.

The lens is fairly new, I love it.  These are difficult shots due to the distance.
Reported Settings.  These are what is recorded in EXIF and, in the case of stacked TC's the f stop is wrong.  I used AV setting of f/11, but the aperture of the lens would have varied according to the TC with it being stopped down more without a TC
Also, it was a winter day and the light varied from shot to shot so the shutter speeds varied according to available light.
No TC  - 1/2500 sec f/11, ISO 800
1.4X - 1/3200 sec f/11 ISO 800
2X   - 1/3200 sec f/11 ISO 800
1.4 + 2X - 1/2000 sec f/11 ISO 800 (not the actual equivalent aperture)
It might be interesting to redo them with my 1D MK IV, but in our near 100 degree weather, the air is too turbulent, and the 1D MK IV is going to be sold soon.

Another thing is: Did you scale the images made with the TC or change the focal length? Comparing the length of the tower by hand doesn't give a magnification of 2x or 2.8x compared to the 1.4x (maybe this is also done on the webpage). I ask this because scaling images is also often problematic and there is quite some discussion on how you should scale the images in order to provide a "fair" comparison.

What we can conclude however is that taking images with a TC is much more complicated than using the bare lens.

Here are some images of Mount Spokane from my back deck for a comparison of my 100-400mmL at 400mm with 1D MK III and Canon TC mk II's.  I've cropped them all to the same view.  With no TC, thats 100% so the image is smaller. They have no post processing other than my lightroom defaults, so obviously they can be improved.

I feel that the 1.4X TC provided the best image, I tried to avoid any motion and used a heavy tripod with underweight, however, with the long TC's, there may have been some vibration, particularly with the 2X.  The top of the mountain is several miles away, so there is a lot of distortion coming from 7 miles of air.

Nice comparison. Could you also post the f-stops used or do you have a stopped down image of the 2x? In my experience the 2x "wide open" doesn't work very well.

Also i have the 2nd hand impression that there are old and new 100-400mm lenses which perform differently. So if you have an old one it wouldn't work as well.

2: you lose f-stops if you put on the TC. (The light gets distributed on an area 2 or 4 times as big, leading to 1 or 2 f-stops loss of light density on the sensor.)
Light density, yes, but not total light, so it's not so bad. For this reason, you can improve signal to noise and dynamic range with a TC compared to cropping since you can collect more photons from the same scene without saturating. (you could of course also take multiple exposures with the same result with the crop)
You can only win here if you increase the exposure time. In total you have more noise compared to cropping or using a camera with smaller pixels, but you also have more photons if you increase the exposure time to overcompensate for that and increase DR and SNR after downscaling.

Lenses / Re: Canon super tele choices!!!
« on: August 13, 2012, 03:46:19 AM »
Mainly for hockey, football, basketball and soccer. I already have the 70-200mm f2.8 so yea. Body I will be using will probably be a 1D IV I will use my 1Ds III if I have to...... ;)

How about an 1.4x extender to your 200mm and a 7D body for a start? Being able to carry the lens without Major Pain sitting on your shoulders is a big benefit in the field.


I did a test once with my 70-200 4.0 L IS and a Canon EF 1.4x II converter. At 200mm, the image quality cropped (to approx. the same field of view) was better than the one with the converter. So no converter for me :)

Did you stop down to f/8 for taking the images? I have a 2x III extender on a 70-200mm L IS II and it is ok (not great but ok) when stepped down. However with increased focal length the exposure time also has to be shorter in order to avoid blur due to shake or movement of the object.

I heard a lot of diverging impressions from people using extenders. You definitely lose resolution and contrast when zoomed to 100% but you still usually gain in detail of a small subject and if you can't carry an additional long lens, the extender is better than cropping. Maybe the differing impressions are from people not adjusting for the longer focal length or due to manufacturing variations of the lenses which become obvious with the additional magnification.

1: your lens needs to outresolve the sensor at the longest focal range. If it doesn't you won't gain anything.

2: you lose f-stops if you put on the TC. (The light gets distributed on an area 2 or 4 times as big, leading to 1 or 2 f-stops loss of light density on the sensor.)

3: Your lens needs to be wide enough to still reach f/5.6 for autofocus. (Autofocus also gets slower with extender due to less light on the focusing mechanism. Low light performance is worse.)

4: you may want to stop down further to f/8 because that usually improves the image quality and resolution.

5: you may need a tripod because 800 mm focal length are hard to hand-hold.

Since you write about the 100-400mm lens on a 22MP FF-body, i assume that it would go well with the 1.4x extender since then the resolution matches a crop body with 18MP without extender. The 2x extender would most likely result in blurred images which don't provide more detail. Also the overall image quality reduces severely with 2x extenders. It's not just resolution but also contrast CA vignetting distortion etc.

What you could try is to use MF and shoot at F/8 without extender and if you can work with that, go for the 1.4x extender (or better yet get a used crop body, which equals to about 1.5x extension but with working AF and no f-stop loss).

EDIT: I may have misunderstood you. Decreasing the sensor size is always better than a TC. So a crop body with all other things equal will always be better. Unfortunately you also have to consider price, weight, different performance of different bodies, different noise characteristics etc... I for myself use a crop body + TC.

Third Party Manufacturers / Re: A Small Sigma 180 f/2.8 OS Macro Issue
« on: August 12, 2012, 04:48:36 PM »
As far as i know, some (all) lenses aren't identified in the EXIF-Data of the image by lens-ID but by parameters like aperture and focal length ranges. Programs have to sort out which lens it actually is from that data. This might be one of the causes for the problem and i don't know how it is done for new lenses.

Third Party Manufacturers / Re: A Small Sigma 180 f/2.8 OS Macro Issue
« on: August 12, 2012, 11:19:50 AM »
IMHO, the best solution for Canon would be to set aside a block of IDs for lenses by companies that reversed engineer the mount protocols, and not doing any lens specific processing for lenses that use an ID in that block.
This would be a very good idea for a start.

Third Party Manufacturers / Re: A Small Sigma 180 f/2.8 OS Macro Issue
« on: August 12, 2012, 06:42:20 AM »
So can we conclude that Canon lenses should be protected like printer ink (more expensive than blood). This can be done with a little security chip built into the lens which identifies it as a genuine Canon. From a certain date on e.g. 1/1/2014 all other lenses will be disabled or set to full manual (no aperture control). It's about time for Canon to step up to these product pirates!

Third Party Manufacturers / Re: A Small Sigma 180 f/2.8 OS Macro Issue
« on: August 11, 2012, 09:59:17 AM »
typicall for sigma.
you wonder if they have a quality management at all.

how can such an issue not be noticed and fixed when developing a lens?

This is NOT a Sigma problem.

It is a Canon problem.
You are very unfair and I totally disagree.

Canon's business is too sell Canon products, not Sigma or Tamron or any other brands.
When Sigma sells 1 lens, Canon does not receive any yen/dollar for that. Why should they care about them? Sigma should already feel happy that Canon doesn't try to definitely inactivate their reverse tech and making their products unusable --> end of business.

Does that then mean that you should buy Canon tripods, Canon monopods, Canon camera bags, etc?
Where do you draw the line?

Canon need to realise that it is the ecosystem around their products that keeps them alive.
If Canon makes a good lens, it will sell. If the competitor is better, Canon needs to "protect their market". If they fall behind not only in the Sensor development but also with the lenses, Canon will have a big problem, because then there's little reason to buy a Canon camera. The lens prices are still up and it's a good time to sell now.

Third Party Manufacturers / Re: A Small Sigma 180 f/2.8 OS Macro Issue
« on: August 11, 2012, 05:26:39 AM »
typicall for sigma.
you wonder if they have a quality management at all.

how can such an issue not be noticed and fixed when developing a lens?
Maybe because it is Canon who broke the compatibility?

Pages: 1 ... 6 7 [8] 9 10 11