Macro wide open - ??
 

On Fri, 01 Jun 2018 07:48:35 -0700, Whisky-dave
wrote in :

On Friday, 1 June 2018 14:59:18 UTC+1, Paul Carmichael wrote:
I'm sure this has been done to death before, but here goes...

Why does my macro lens (Tamron SP90) open up to 2.5?

Does it ? as it seems to state f2.8 on the web.

It could be that the firmware of the camera has access to the lense T
value in its database. PC uses a fairly modern EOS 6D mark II, IIRC.
There is according to DxO Mark two different Tammies 90SP one T/3.0 and
the other, newer T/3.3. The latter would be more like 2.5 rather than 2.8
if the former is used for reference... HTH!

https://www.dxomark.com/lenses/brand...-between-1987-
and-2018/mount_type-Canon_EF/focal-from-90-to-90/launch_price-from-0-
to-13000-usd#hideAdvancedOptions=false&viewMode=list&yDataT ype=global

--
teleportation kills

Macro wide open - ??
 

In article , android
wrote:

Why does my macro lens (Tamron SP90) open up to 2.5?

Does it ? as it seems to state f2.8 on the web.

It could be that the firmware of the camera has access to the lense T
value in its database. PC uses a fairly modern EOS 6D mark II, IIRC.
There is according to DxO Mark two different Tammies 90SP one T/3.0 and
the other, newer T/3.3. The latter would be more like 2.5 rather than 2.8
if the former is used for reference... HTH!

or it could actually be f/2.5
http://www.adaptall-2.com/lenses/52B.html

Macro wide open - ??
 

On Fri, 01 Jun 2018 11:30:25 -0400, nospam wrote
in lid:

In article , android
wrote:

Why does my macro lens (Tamron SP90) open up to 2.5?

Does it ? as it seems to state f2.8 on the web.

It could be that the firmware of the camera has access to the lense T
value in its database. PC uses a fairly modern EOS 6D mark II, IIRC.
There is according to DxO Mark two different Tammies 90SP one T/3.0 and
the other, newer T/3.3. The latter would be more like 2.5 rather than
2.8 if the former is used for reference... HTH!

or it could actually be f/2.5
http://www.adaptall-2.com/lenses/52B.html

Sure. But that would not be reported from lense to camera.

--
teleportation kills

Macro wide open - ??
 

In article , android
wrote:

Why does my macro lens (Tamron SP90) open up to 2.5?

Does it ? as it seems to state f2.8 on the web.

It could be that the firmware of the camera has access to the lense T
value in its database. PC uses a fairly modern EOS 6D mark II, IIRC.
There is according to DxO Mark two different Tammies 90SP one T/3.0 and
the other, newer T/3.3. The latter would be more like 2.5 rather than
2.8 if the former is used for reference... HTH!

or it could actually be f/2.5
http://www.adaptall-2.com/lenses/52B.html

Sure. But that would not be reported from lense to camera.

he didn't say it was reported to the camera.

he only asked why it opens up to f/2.5, which is for a shallow depth of
field and/or low light, like any other lens.

Macro wide open - ??
 

On Fri, 01 Jun 2018 11:40:38 -0400, nospam wrote
in lid:

In article , android
wrote:

Why does my macro lens (Tamron SP90) open up to 2.5?

Does it ? as it seems to state f2.8 on the web.

It could be that the firmware of the camera has access to the lense
T value in its database. PC uses a fairly modern EOS 6D mark II,
IIRC. There is according to DxO Mark two different Tammies 90SP one
T/3.0 and the other, newer T/3.3. The latter would be more like 2.5
rather than 2.8 if the former is used for reference... HTH!

or it could actually be f/2.5
http://www.adaptall-2.com/lenses/52B.html

Sure. But that would not be reported from lense to camera.

he didn't say it was reported to the camera.

he only asked why it opens up to f/2.5, which is for a shallow depth of
field and/or low light, like any other lens.

That should be a non issue if marked on the lense...



--
teleportation kills

Macro wide open - ??
 

In article , Paul Carmichael
wrote:

or it could actually be f/2.5
http://www.adaptall-2.com/lenses/52B.html

Sure. But that would not be reported from lense to camera.

he didn't say it was reported to the camera.

he only asked why it opens up to f/2.5, which is for a shallow depth of
field and/or low light, like any other lens.


Is low light ever an issue with macro photography?

not usually, but that doesn't mean never.

or, a fast shutter speed is desired, which would require a wide
aperture (or crank the iso, but that adds noise).

As for shallow depth of
field, that's
exactly what I'm saying. Wide open it won't get past a fly's eyeballs. So
that's it then,
some people like to take photos of fly's eyeballs. Seems a bit of a waste of glass to me.

flies aren't the only macro subject.

it could be something flat, like a postage stamp, where shallow dof
doesn't matter much.

Macro wide open - ??
 

On Fri, 01 Jun 2018 18:33:36 +0200, Paul Carmichael
wrote in :

On 01/06/18 17:39, android wrote:
On Fri, 01 Jun 2018 11:30:25 -0400, nospam
wrote in lid:

In article , android
wrote:

Why does my macro lens (Tamron SP90) open up to 2.5?

Does it ? as it seems to state f2.8 on the web.

It could be that the firmware of the camera has access to the lense T
value in its database. PC uses a fairly modern EOS 6D mark II, IIRC.
There is according to DxO Mark two different Tammies 90SP one T/3.0
and the other, newer T/3.3. The latter would be more like 2.5 rather
than 2.8 if the former is used for reference... HTH!

or it could actually be f/2.5
http://www.adaptall-2.com/lenses/52B.html

Sure. But that would not be reported from lense to camera.


I chipped the adaptall. So yes, it is.

Then you would need to program the chip to report that that you want it
to report...

--
teleportation kills

Macro wide open - ??
 

On Sat, 02 Jun 2018 10:01:22 +0200, Paul Carmichael
wrote in :

On 01/06/18 19:09, android wrote:
On Fri, 01 Jun 2018 18:33:36 +0200, Paul Carmichael
wrote in :

On 01/06/18 17:39, android wrote:
On Fri, 01 Jun 2018 11:30:25 -0400, nospam
wrote in lid:

In article , android
wrote:

Why does my macro lens (Tamron SP90) open up to 2.5?

Does it ? as it seems to state f2.8 on the web.

It could be that the firmware of the camera has access to the lense
T value in its database. PC uses a fairly modern EOS 6D mark II,
IIRC. There is according to DxO Mark two different Tammies 90SP one
T/3.0 and the other, newer T/3.3. The latter would be more like 2.5
rather than 2.8 if the former is used for reference... HTH!

or it could actually be f/2.5
http://www.adaptall-2.com/lenses/52B.html

Sure. But that would not be reported from lense to camera.


I chipped the adaptall. So yes, it is.

Then you would need to program the chip to report that that you want it
to report...


Well obviously. And knowing that the lens is 2.5-22, that's what I
programmed it as.

You were kind enough to post a link to a picture with the full exif, and
it does not seem to be programmed at all:

Make - Canon
X-Resolution - 240 dpi
Y-Resolution - 240 dpi
Software - Adobe Photoshop Lightroom 6.14 (Windows)
Date and Time (Modified) - 2018:06:02 11:57:16
Artist - PAUL CARMICHAEL
Copyright - Paul Carmichael
ISO Speed - 400
Sensitivity Type - Recommended Exposure Index
Recommended Exposure Index - 400
Exif Version - 0230
Date and Time (Original) - 2018:06:01 14:07:22
Date and Time (Digitized) - 2018:06:01 14:07:22
Exposure Bias - 0 EV
Max Aperture Value - 2.5
Metering Mode - Spot
Sub Sec Time Original - 45
Sub Sec Time Digitized - 45
Color Space - sRGB
Focal Plane X-Resolution - 1736.671661
Focal Plane Y-Resolution - 1736.671661
Focal Plane Resolution Unit - cm
Custom Rendered - Normal
Exposure Mode - Manual
White Balance - Auto
Scene Capture Type - Standard
Lens Info - 1-65535mm f/?
Lens Model - 1-65535mm
Lens Serial Number - 0000000000
Compression - JPEG (old-style)
Thumbnail Offset - 924
Thumbnail Length - 9204
Displayed Units X - inches
Displayed Units Y - inches
Photoshop Thumbnail - (Binary data 9204 bytes, use -b option to extract)
IPTCDigest - da8e5702bcc8319be00c7ea61cbf483c
Coded Character Set - UTF8
Application Record Version - 4
Date Created - 2018:06:01
Time Created - 14:07:22
Digital Creation Date - 2018:06:01
Digital Creation Time - 14:07:22
By-line - PAUL CARMICHAEL
Copyright Notice - Paul Carmichael
Viewing Cond Illuminant - 19.6445 20.3718 16.8089
Viewing Cond Surround - 3.92889 4.07439 3.36179
Viewing Conditions Illuminant Type - D50
Measurement Observer - CIE 1931
Measurement Backing - 0 0 0
Measurement Geometry - Unknown (0)
Measurement Flare - 0.999%
Measurement Illuminant - D65
XMPToolkit - Adobe XMP Core 5.6-c128 79.159124, 2016/03/18-14:01:55
Creator Tool - Adobe Photoshop Lightroom 6.14 (Windows)
Metadata Date - 2018:06:02 11:57:16+02:00
Format - image/jpeg
Creator - PAUL CARMICHAEL
Rights - Paul Carmichael
Lens ID - 27
Image Number - 0
Flash Compensation - 0
Firmware - 1.0.3
Document ID - xmp.did:05a22f79-0fc0-2346-9f19-9bc9f898e189
Original Document ID - 4F1C3E75149E495551660044089B79B5
Instance ID - xmp.iid:05a22f79-0fc0-2346-9f19-9bc9f898e189
History Action - derived
History Parameters - converted from image/x-canon-cr2 to image/jpeg,
saved to new location
History Instance ID - xmp.iid:05a22f79-0fc0-2346-9f19-9bc9f898e189
History When - 2018:06:02 11:57:16+02:00
History Software Agent - Adobe Photoshop Lightroom 6.14 (Windows)
History Changed - /
Derived From Document ID - 4F1C3E75149E495551660044089B79B5
Derived From Original Document ID - 4F1C3E75149E495551660044089B79B5
DCTEncode Version - 100
APP14 Flags0 - [14], Encoded with Blend=1 downsampling
APP14 Flags1 - (none)
Color Transform - YCbCr
Camera ID - 72157662779818774
Camera Type - Digital SLR

https://www.flickr.com/photos/wibble...in/dateposted-
family/

--
teleportation kills

Macro wide open - ??
 

On Sun, 03 Jun 2018 13:42:02 +0200, Paul Carmichael
wrote in :

On 03/06/18 06:01, android wrote:
On Sat, 02 Jun 2018 10:01:22 +0200, Paul Carmichael
wrote in :

On 01/06/18 19:09, android wrote:
On Fri, 01 Jun 2018 18:33:36 +0200, Paul Carmichael
wrote in :

On 01/06/18 17:39, android wrote:
On Fri, 01 Jun 2018 11:30:25 -0400, nospam
wrote in lid:

In article ,
android wrote:

Why does my macro lens (Tamron SP90) open up to 2.5?

Does it ? as it seems to state f2.8 on the web.

It could be that the firmware of the camera has access to the
lense T value in its database. PC uses a fairly modern EOS 6D
mark II, IIRC. There is according to DxO Mark two different
Tammies 90SP one T/3.0 and the other, newer T/3.3. The latter
would be more like 2.5 rather than 2.8 if the former is used for
reference... HTH!

or it could actually be f/2.5
http://www.adaptall-2.com/lenses/52B.html

Sure. But that would not be reported from lense to camera.


I chipped the adaptall. So yes, it is.

Then you would need to program the chip to report that that you want
it to report...


Well obviously. And knowing that the lens is 2.5-22, that's what I
programmed it as.

You were kind enough to post a link to a picture with the full exif,
and it does not seem to be programmed at all:

I don't get your point. Do you know how these chips work? The chip tells
the camera that it's a 90mm lens. I have to tell the camera the aperture
setting. It won't let me go below 2.5 or over 22 (I "programmed" the
chip to know it's a 90mm lens with aperture between 2.5 and 22). What I
tell the camera is what's reported in the exif. Obviously the chip can't
know what I've set the aperture to. Also, the chip enables focus
confirmation. They are generally sold as "focus confirmation chips".

Exif:

Max Aperture Value - 2.5

Oki...

"Capture Type - Standard Lens Info - 1-65535mm f/?
Lens Model - 1-65535mm Lens Serial Number - 0000000000 Compression - JPEG
(old-style)"

Not a very complete programing then... And you complaint against your
lense was?
--
teleportation kills

Macro wide open - ??
 

On Sun, 03 Jun 2018 15:36:12 +0200, Paul Carmichael
wrote in :

On 03/06/18 15:27, android wrote:
On Sun, 03 Jun 2018 13:42:02 +0200, Paul Carmichael
wrote in :

On 03/06/18 06:01, android wrote:
On Sat, 02 Jun 2018 10:01:22 +0200, Paul Carmichael
wrote in :

On 01/06/18 19:09, android wrote:
On Fri, 01 Jun 2018 18:33:36 +0200, Paul Carmichael
wrote in :

On 01/06/18 17:39, android wrote:
On Fri, 01 Jun 2018 11:30:25 -0400, nospam

wrote in lid:

In article ,
android wrote:

Why does my macro lens (Tamron SP90) open up to 2.5?

Does it ? as it seems to state f2.8 on the web.

It could be that the firmware of the camera has access to the
lense T value in its database. PC uses a fairly modern EOS 6D
mark II, IIRC. There is according to DxO Mark two different
Tammies 90SP one T/3.0 and the other, newer T/3.3. The latter
would be more like 2.5 rather than 2.8 if the former is used
for reference... HTH!

or it could actually be f/2.5
http://www.adaptall-2.com/lenses/52B.html

Sure. But that would not be reported from lense to camera.


I chipped the adaptall. So yes, it is.

Then you would need to program the chip to report that that you
want it to report...


Well obviously. And knowing that the lens is 2.5-22, that's what I
programmed it as.

You were kind enough to post a link to a picture with the full exif,
and it does not seem to be programmed at all:

I don't get your point. Do you know how these chips work? The chip
tells the camera that it's a 90mm lens. I have to tell the camera the
aperture setting. It won't let me go below 2.5 or over 22 (I
"programmed" the chip to know it's a 90mm lens with aperture between
2.5 and 22). What I tell the camera is what's reported in the exif.
Obviously the chip can't know what I've set the aperture to. Also, the
chip enables focus confirmation. They are generally sold as "focus
confirmation chips".

Exif:

Max Aperture Value - 2.5

Oki...

"Capture Type - Standard Lens Info - 1-65535mm f/?
Lens Model - 1-65535mm Lens Serial Number - 0000000000 Compression -
JPEG (old-style)"

Not a very complete programing then... And you complaint against your
lense was?


What is is with you? Did you not read what I wrote?

Sure did. You can't take the heat well, do ya?

And what complaint
are you talking about?

This one:

On Fri, 01 Jun 2018 15:59:10 +0200, Paul Carmichael
wrote in :

I'm sure this has been done to death before, but here goes...

Why does my macro lens (Tamron SP90) open up to 2.5?

So it's made that way!

Unless it's to take photos of a molecule, what's the point?

With your lense? I does focus beyond 5cm don't it?

The last question was rhetorical...

https://en.wiktionary.org/wiki/rhetorical_question#English
--
teleportation kills